Update composer.json changed the cweagans/composer-patches to use 1.6.3...

Update composer.json changed the cweagans/composer-patches to use 1.6.3 instead of dev-master to stop it breaking our build.

composer.json

@@ -312,7 +312,7 @@
         "behat/mink": "~1.7",
         "behat/mink-goutte-driver": "~1.2",
         "composer/installers": "^1.2",
-        "cweagans/composer-patches": "dev-master",
+        "cweagans/composer-patches": "1.6.3",
         "ckeditor/autogrow": "4.9.0",
         "ckeditor/codemirror": "v1.17.3",
         "ckeditor/fakeobjects": "4.9.0",