Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/masterminds/html5/composer.json

@@ -0,0 +1,42 @@
+{
+    "name": "masterminds/html5",
+    "description": "An HTML5 parser and serializer.",
+    "type": "library",
+    "homepage": "http://masterminds.github.io/html5-php",
+    "license": "MIT",
+    "keywords": ["xml", "html", "html5", "dom", "parser", "serializer", "querypath"],
+    "authors": [
+        {
+            "name": "Matt Butcher",
+            "email": "technosophos@gmail.com"
+        },
+        {
+            "name": "Matt Farina",
+            "email": "matt@mattfarina.com"
+        },
+        {
+            "name": "Asmir Mustafic",
+            "email": "goetas@gmail.com"
+        }
+    ],
+    "require" : {
+        "ext-libxml" : "*",
+        "php" : ">=5.3.0"
+    },
+    "require-dev": {
+        "satooshi/php-coveralls": "0.6.*",
+        "phpunit/phpunit" : "4.*",
+        "sami/sami": "~2.0"
+    },
+    "autoload": {
+        "psr-4": {"Masterminds\\": "src"}
+    },
+    "autoload-dev": {
+        "psr-4": {"Masterminds\\HTML5\\Tests\\": "test/HTML5"}
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.1-dev"
+        }
+    }
+}