Bump github.com/prometheus/client_model from 0.5.0 to 0.6.0 (#3367)

Bumps [github.com/prometheus/client_model](https://github.com/prometheus/client_model) from 0.5.0 to 0.6.0.
- [Release notes](https://github.com/prometheus/client_model/releases)
- [Commits](prometheus/client_model@v0.5.0...v0.6.0)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_model
  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>

go.mod

@@ -19,7 +19,7 @@ require (
 	github.com/letsencrypt/pkcs11key/v4 v4.0.0
 	github.com/lib/pq v1.10.9
 	github.com/prometheus/client_golang v1.18.0
-	github.com/prometheus/client_model v0.5.0
+	github.com/prometheus/client_model v0.6.0
 	github.com/pseudomuto/protoc-gen-doc v1.5.1
 	github.com/transparency-dev/merkle v0.0.2
 	go.etcd.io/etcd/client/v3 v3.5.12

go.sum

@@ -541,8 +541,8 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH
 github.com/prometheus/client_golang v1.18.0 h1:HzFfmkOzH5Q8L8G+kSJKUx5dtG87sewO+FoDDqP5Tbk=
 github.com/prometheus/client_golang v1.18.0/go.mod h1:T+GXkCk5wSJyOqMIzVgvvjFDlkOQntgjkJWKrN5txjA=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
-github.com/prometheus/client_model v0.5.0 h1:VQw1hfvPvk3Uv6Qf29VrPF32JB6rtbgI6cYPYQjL0Qw=
-github.com/prometheus/client_model v0.5.0/go.mod h1:dTiFglRmd66nLR9Pv9f0mZi7B7fk5Pm3gvsjB5tr+kI=
+github.com/prometheus/client_model v0.6.0 h1:k1v3CzpSRUTrKMppY35TLwPvxHqBu0bYgxZzqGIgaos=
+github.com/prometheus/client_model v0.6.0/go.mod h1:NTQHnmxFpouOD0DpvP4XujX3CdOAGQPoaGhyTchlyt8=
 github.com/prometheus/common v0.45.0 h1:2BGz0eBc2hdMDLnO/8n0jeB3oPrt2D08CekT0lneoxM=
 github.com/prometheus/common v0.45.0/go.mod h1:YJmSTw9BoKxJplESWWxlbyttQR4uaEcGyv9MZjVOJsY=
 github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=