Bump ember-cli-babel from 7.19.0 to 7.20.0

Bumps [ember-cli-babel](https://github.com/babel/ember-cli-babel) from 7.19.0 to 7.20.0.
- [Release notes](https://github.com/babel/ember-cli-babel/releases)
- [Changelog](https://github.com/babel/ember-cli-babel/blob/master/CHANGELOG.md)
- [Commits](emberjs/ember-cli-babel@v7.19.0...v7.20.0)

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Author: dependabot-preview[bot]