Bump @vue/cli-plugin-babel from 4.5.4 to 4.5.6

Bumps [@vue/cli-plugin-babel](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-plugin-babel) from 4.5.4 to 4.5.6.
- [Release notes](https://github.com/vuejs/vue-cli/releases)
- [Changelog](https://github.com/vuejs/vue-cli/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vue-cli/commits/v4.5.6/packages/@vue/cli-plugin-babel)

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

Author: dependabot-preview[bot]