fix(package): update graphql-tools to version 6.0.3

Closes #15

Author: greenkeeper[bot]

package.json

@@ -9,7 +9,7 @@
     "apollo-link-schema": "^1.1.1",
     "graphql": "^14.0.2",
     "graphql-tag": "^2.10.0",
-    "graphql-tools": "^4.0.2",
+    "graphql-tools": "^6.0.3",
     "react": "^16.6.0",
     "react-apollo": "^2.2.4",
     "react-dom": "^16.6.0",