add license (Apache2)

LICENSE

+   Copyright 2019 ValueFlows contributors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

lib/package.json

@@ -34,7 +34,7 @@
     "grammar"
   ],
   "author": "ValueFlows contributors",
-  "license": "MIT",
+  "license": "Apache2",
   "bugs": {
     "url": "https://github.com/valueflows/vf-graphql/issues"
   },