Bump @babel/polyfill from 7.11.5 to 7.12.1

Bumps [@babel/polyfill](https://github.com/babel/babel/tree/HEAD/packages/babel-polyfill) from 7.11.5 to 7.12.1.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/main/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/commits/v7.12.1/packages/babel-polyfill)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -11,7 +11,7 @@
     "@babel/plugin-proposal-class-properties": "^7.10.1",
     "@babel/plugin-proposal-private-methods": "^7.10.1",
     "@babel/plugin-transform-modules-amd": "^7.10.5",
-    "@babel/polyfill": "^7.11.5",
+    "@babel/polyfill": "^7.12.1",
     "@babel/preset-env": "^7.11.5",
     "autoprefixer": "^9.8.6",
     "babel-loader": "^8.0.6",