chore(release): 1.6.0 [skip ci]

# [1.6.0](https://gitlab.com/to-be-continuous/docker-compose/compare/1.5.0...1.6.0) (2025-12-22)

### Features

* add vault variant ([6a0ebe91](https://gitlab.com/to-be-continuous/docker-compose/commit/6a0ebe9112a1bb7a09d0a241a0829f3a1b628334))