Bump vlucas/phpdotenv from 5.5.0 to 5.6.0

Bumps [vlucas/phpdotenv](https://github.com/vlucas/phpdotenv) from 5.5.0 to 5.6.0.
- [Release notes](https://github.com/vlucas/phpdotenv/releases)
- [Commits](vlucas/phpdotenv@v5.5.0...v5.6.0)

---
updated-dependencies:
- dependency-name: vlucas/phpdotenv
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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