Bump vue-loader from 14.2.2 to 15.2.4

Bumps [vue-loader](https://github.com/vuejs/vue-loader) from 14.2.2 to 15.2.4.
- [Release notes](https://github.com/vuejs/vue-loader/releases)
- [Changelog](https://github.com/vuejs/vue-loader/blob/master/CHANGELOG.md)
- [Commits](vuejs/vue-loader@v14.2.2...v15.2.4)

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

Author: dependabot-support