Bump laravel-mix from 6.0.27 to 6.0.29

Bumps [laravel-mix](https://github.com/JeffreyWay/laravel-mix) from 6.0.27 to 6.0.29.
- [Release notes](https://github.com/JeffreyWay/laravel-mix/releases)
- [Changelog](https://github.com/laravel-mix/laravel-mix/blob/master/CHANGELOG.md)
- [Commits](https://github.com/JeffreyWay/laravel-mix/commits)

---
updated-dependencies:
- dependency-name: laravel-mix
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]