Enabled some more polyfills

package.json

@@ -46,6 +46,7 @@
     "rxjs": "~6.4.0",
     "tslib": "^1.9.0",
     "web-animations-js": "^2.3.2",
+    "whatwg-fetch": "^3.0.0",
     "zone.js": "~0.9.1"
   },
   "devDependencies": {

src/polyfills.ts

@@ -56,7 +56,7 @@ import 'web-animations-js';  // Run `npm install --save web-animations-js`.
  * Zone JS is required by default for Angular itself.
  */
 import 'zone.js/dist/zone';  // Included with Angular CLI.
-
+import 'whatwg-fetch'; // Run `npm install --save whatwg-fetch`
 
 /***************************************************************************************************
  * APPLICATION IMPORTS

yarn.lock

@@ -8087,7 +8087,7 @@ whatwg-fetch@2.0.4:
   resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-2.0.4.tgz#dde6a5df315f9d39991aa17621853d720b85566f"
   integrity sha512-dcQ1GWpOD/eEQ97k66aiEVpNnapVj90/+R+SXTPYGHpYBBypfKJEQjLrvMZ7YXbKm21gXd4NcuxUTjiv1YtLng==
 
-whatwg-fetch@>=0.10.0:
+whatwg-fetch@>=0.10.0, whatwg-fetch@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-3.0.0.tgz#fc804e458cc460009b1a2b966bc8817d2578aefb"
   integrity sha512-9GSJUgz1D4MfyKU7KRqwOjXCXTqWdFNvEr7eUBYchQiVc744mqK/MzXPNR2WsPkmkOa4ywfg8C2n8h+13Bey1Q==