Bump @babel/polyfill from 7.4.3 to 7.12.1

Bumps [@babel/polyfill](https://github.com/babel/babel/tree/HEAD/packages/babel-polyfill) from 7.4.3 to 7.12.1.
- [Release notes](https://github.com/babel/babel/releases)
- [Commits](https://github.com/babel/babel/commits/v7.12.1/packages/babel-polyfill)

---
updated-dependencies:
- dependency-name: "@babel/polyfill"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]