Merge pull request #550 from halfzebra/renovate/whatwg-fetch-3.x

feat(package.json): Update dependency whatwg-fetch to v3.5.0

Author: renovate[bot]

package.json

@@ -64,7 +64,7 @@
     "webpack": "4.44.2",
     "webpack-dev-server": "3.11.0",
     "webpack-manifest-plugin": "2.2.0",
-    "whatwg-fetch": "3.4.1",
+    "whatwg-fetch": "3.5.0",
     "workbox-webpack-plugin": "4.3.1"
   },
   "devDependencies": {