chore(package): update graphql-tools to version 3.0.4

Closes #14

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "@types/lodash": "^4.14.80",
     "@types/minimatch": "^3.0.1",
     "ava": "^0.23.0",
-    "graphql-tools": "^2.6.1",
+    "graphql-tools": "^3.0.4",
     "typescript": "^2.5.2"
   }
 }