chore(deps): bump github.com/prometheus/client_golang

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/master/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.5.1...v1.6.0

)

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