Bump @vue/cli-plugin-babel in /Rnwood.Smtp4dev/ClientApp

Bumps [@vue/cli-plugin-babel](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-plugin-babel) from 4.5.13 to 4.5.15.
- [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/v4.5.15/packages/@vue/cli-plugin-babel)

---
updated-dependencies:
- dependency-name: "@vue/cli-plugin-babel"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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