fix(package): update cross-fetch to version 3.0.0

Author: greenkeeper[bot]

package.json

@@ -18,7 +18,7 @@
   },
   "dependencies": {
     "apollo-boost": "^0.1.22",
-    "cross-fetch": "^2.2.3",
+    "cross-fetch": "^3.0.0",
     "dotenv": "^6.1.0",
     "graphql": "^14.0.2"
   }