build(deps): bump github.com/hashicorp/vault from 1.17.0-rc1 to 1.21.0

Bumps [github.com/hashicorp/vault](https://github.com/hashicorp/vault) from 1.17.0-rc1 to 1.21.0.
- [Release notes](https://github.com/hashicorp/vault/releases)
- [Changelog](https://github.com/hashicorp/vault/blob/main/CHANGELOG.md)
- [Commits](hashicorp/vault@v1.17.0-rc1...v1.21.0)

---
updated-dependencies:
- dependency-name: github.com/hashicorp/vault
  dependency-version: 1.21.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]