Fix for Peertube videos.

activitypub.c

@@ -390,6 +390,11 @@ xs_list *get_attachments(const xs_dict *msg)
                             }
                         }
                     }
+                    else
+                    if (xs_is_string(mtype) && strcmp(mtype, "video/mp4") == 0) {
+                        href = xs_dict_get(v, "href");
+                        type = mtype;
+                    }
                 }
             }
         }