Bump github.com/prometheus/client_golang from 1.20.5 to 1.21.0

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.20.5 to 1.21.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/main/CHANGELOG.md)
- [Commits](prometheus/client_golang@v1.20.5...v1.21.0)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -22,7 +22,7 @@ require (
 	github.com/jackc/pgx/v5 v5.7.2
 	github.com/knadh/koanf v1.5.0
 	github.com/mitchellh/mapstructure v1.5.0
-	github.com/prometheus/client_golang v1.20.5
+	github.com/prometheus/client_golang v1.21.0
 	github.com/prometheus/client_model v0.6.1
 	github.com/prometheus/common v0.62.0
 	github.com/redis/go-redis/v9 v9.7.0