Bump phpunit/phpunit from 5.6.3 to 5.7.27

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 5.6.3 to 5.7.27.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/5.7.27/ChangeLog-5.7.md)
- [Commits](https://github.com/sebastianbergmann/phpunit/compare/5.6.3...5.7.27)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.lock

@@ -845,16 +845,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "5.6.3",
+            "version": "5.7.27",
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                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "a9de0dbafeb6b1391b391fbb034734cb0af9f67c"
+                "reference": "b7803aeca3ccb99ad0a506fa80b64cd6a56bbc0c"
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-                "reference": "a9de0dbafeb6b1391b391fbb034734cb0af9f67c",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/b7803aeca3ccb99ad0a506fa80b64cd6a56bbc0c",
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             "require": {
@@ -865,21 +865,21 @@
                 "ext-xml": "*",
                 "myclabs/deep-copy": "~1.3",
                 "php": "^5.6 || ^7.0",
-                "phpspec/prophecy": "^1.3.1",
-                "phpunit/php-code-coverage": "^4.0.1",
+                "phpspec/prophecy": "^1.6.2",
+                "phpunit/php-code-coverage": "^4.0.4",
                 "phpunit/php-file-iterator": "~1.4",
                 "phpunit/php-text-template": "~1.2",
                 "phpunit/php-timer": "^1.0.6",
                 "phpunit/phpunit-mock-objects": "^3.2",
-                "sebastian/comparator": "~1.1",
-                "sebastian/diff": "~1.2",
-                "sebastian/environment": "^1.3 || ^2.0",
-                "sebastian/exporter": "~1.2",
-                "sebastian/global-state": "~1.0",
-                "sebastian/object-enumerator": "~1.0",
+                "sebastian/comparator": "^1.2.4",
+                "sebastian/diff": "^1.4.3",
+                "sebastian/environment": "^1.3.4 || ^2.0",
+                "sebastian/exporter": "~2.0",
+                "sebastian/global-state": "^1.1",
+                "sebastian/object-enumerator": "~2.0",
                 "sebastian/resource-operations": "~1.0",
-                "sebastian/version": "~1.0|~2.0",
-                "symfony/yaml": "~2.1|~3.0"
+                "sebastian/version": "^1.0.6|^2.0.1",
+                "symfony/yaml": "~2.1|~3.0|~4.0"
             },
             "conflict": {
                 "phpdocumentor/reflection-docblock": "3.0.2"
@@ -897,7 +897,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "5.6.x-dev"
+                    "dev-master": "5.7.x-dev"
                 }
             },
             "autoload": {
@@ -925,9 +925,9 @@
             ],
             "support": {
                 "issues": "https://github.com/sebastianbergmann/phpunit/issues",
-                "source": "https://github.com/sebastianbergmann/phpunit/tree/5.6.3"
+                "source": "https://github.com/sebastianbergmann/phpunit/tree/5.7.27"
             },
-            "time": "2016-11-14T06:39:40+00:00"
+            "time": "2018-02-01T05:50:59+00:00"
         },
         {
             "name": "phpunit/phpunit-mock-objects",
@@ -1229,21 +1229,21 @@
         },
         {
             "name": "sebastian/exporter",
-            "version": "1.2.2",
+            "version": "2.0.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/exporter.git",
-                "reference": "42c4c2eec485ee3e159ec9884f95b431287edde4"
+                "reference": "ce474bdd1a34744d7ac5d6aad3a46d48d9bac4c4"
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-                "reference": "42c4c2eec485ee3e159ec9884f95b431287edde4",
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+                "reference": "ce474bdd1a34744d7ac5d6aad3a46d48d9bac4c4",
                 "shasum": ""
             },
             "require": {
                 "php": ">=5.3.3",
-                "sebastian/recursion-context": "~1.0"
+                "sebastian/recursion-context": "~2.0"
             },
             "require-dev": {
                 "ext-mbstring": "*",
@@ -1252,7 +1252,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.3.x-dev"
+                    "dev-master": "2.0.x-dev"
                 }
             },
             "autoload": {
@@ -1296,7 +1296,7 @@
                 "issues": "https://github.com/sebastianbergmann/exporter/issues",
                 "source": "https://github.com/sebastianbergmann/exporter/tree/master"
             },
-            "time": "2016-06-17T09:04:28+00:00"
+            "time": "2016-11-19T08:54:04+00:00"
         },
         {
             "name": "sebastian/global-state",
@@ -1355,21 +1355,21 @@
         },
         {
             "name": "sebastian/object-enumerator",
-            "version": "1.0.0",
+            "version": "2.0.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/object-enumerator.git",
-                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26"
+                "reference": "1311872ac850040a79c3c058bea3e22d0f09cbb7"
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-                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26",
+                "url": "https://api.github.com/repos/sebastianbergmann/object-enumerator/zipball/1311872ac850040a79c3c058bea3e22d0f09cbb7",
+                "reference": "1311872ac850040a79c3c058bea3e22d0f09cbb7",
                 "shasum": ""
             },
             "require": {
                 "php": ">=5.6",
-                "sebastian/recursion-context": "~1.0"
+                "sebastian/recursion-context": "~2.0"
             },
             "require-dev": {
                 "phpunit/phpunit": "~5"
@@ -1377,7 +1377,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.0.x-dev"
+                    "dev-master": "2.0.x-dev"
                 }
             },
             "autoload": {
@@ -1401,20 +1401,20 @@
                 "issues": "https://github.com/sebastianbergmann/object-enumerator/issues",
                 "source": "https://github.com/sebastianbergmann/object-enumerator/tree/master"
             },
-            "time": "2016-01-28T13:25:10+00:00"
+            "time": "2017-02-18T15:18:39+00:00"
         },
         {
             "name": "sebastian/recursion-context",
-            "version": "1.0.5",
+            "version": "2.0.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/recursion-context.git",
-                "reference": "b19cc3298482a335a95f3016d2f8a6950f0fbcd7"
+                "reference": "2c3ba150cbec723aa057506e73a8d33bdb286c9a"
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-                "reference": "b19cc3298482a335a95f3016d2f8a6950f0fbcd7",
+                "url": "https://api.github.com/repos/sebastianbergmann/recursion-context/zipball/2c3ba150cbec723aa057506e73a8d33bdb286c9a",
+                "reference": "2c3ba150cbec723aa057506e73a8d33bdb286c9a",
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             "require": {
@@ -1426,7 +1426,7 @@
             "type": "library",
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                 "branch-alias": {
-                    "dev-master": "1.0.x-dev"
+                    "dev-master": "2.0.x-dev"
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             "autoload": {
@@ -1458,7 +1458,7 @@
                 "issues": "https://github.com/sebastianbergmann/recursion-context/issues",
                 "source": "https://github.com/sebastianbergmann/recursion-context/tree/master"
             },
-            "time": "2016-10-03T07:41:43+00:00"
+            "time": "2016-11-19T07:33:16+00:00"
         },
         {
             "name": "sebastian/resource-operations",