Bump prometheus from 0.11.0 to 0.12.0
Bump prometheus from 0.11.0 to 0.12.0

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)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat