chore(release): 4.0.0 [skip ci]

# [4.0.0](https://gitlab.com/to-be-continuous/helmfile/compare/3.5.0...4.0.0) (2025-08-13)

* feat(vault)!: enable certificate verification ([db165d77](https://gitlab.com/to-be-continuous/helmfile/commit/db165d77f4a0929071f09d51d66507c7e4a210f0))

### BREAKING CHANGES

* self-signed certificates must be declared in your GitLab DEFAULT_CA_CERTS or with VAULT_CA_CERTS variable