Bump prometheus from 0.11.0 to 0.12.0 (#9454)

Bumps [prometheus](https://github.com/tikv/rust-prometheus) from 0.11.0 to 0.12.0.
- [Release notes](https://github.com/tikv/rust-prometheus/releases)
- [Changelog](https://github.com/tikv/rust-prometheus/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tikv/rust-prometheus/compare/v0.11.0...v0.12.0

)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>