build(deps): Bump testcontainers from 0.20.1 to 0.21.0

Bumps [testcontainers](https://github.com/testcontainers/testcontainers-rs) from 0.20.1 to 0.21.0.
- [Release notes](https://github.com/testcontainers/testcontainers-rs/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-rs/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-rs@0.20.1...0.21.0)

---
updated-dependencies:
- dependency-name: testcontainers
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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