feat: upgrade react-app-polyfill from 2.0.0 to 3.0.0 (#391)

Snyk has created this PR to upgrade react-app-polyfill from 2.0.0 to 3.0.0.

See this package in npm:
https://www.npmjs.com/package/react-app-polyfill

See this project in Snyk:
https://app.snyk.io/org/helsearbeidsgiver/project/8e6cf866-6de1-4306-a9c3-92d168657a92?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -82,7 +82,7 @@
     "nav-frontend-veilederpanel-style": "^2.0.1",
     "prop-types": "^15.8.1",
     "react": "^17.0.2",
-    "react-app-polyfill": "^2.0.0",
+    "react-app-polyfill": "^3.0.0",
     "react-day-picker": "^7.4.10",
     "react-dom": "^17.0.2",
     "react-hook-form": "^7.20.5",