rebase: bump github.com/prometheus/client_golang from 1.14.0 to 1.15.1

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.14.0 to 1.15.1.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/main/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.14.0...v1.15.1)

---
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>

vendor/github.com/prometheus/procfs/proc_stat.go

@@ -102,6 +102,8 @@ type ProcStat struct {
 	RSS int
 	// Soft limit in bytes on the rss of the process.
 	RSSLimit uint64
+	// CPU number last executed on.
+	Processor uint
 	// Real-time scheduling priority, a number in the range 1 to 99 for processes
 	// scheduled under a real-time policy, or 0, for non-real-time processes.
 	RTPriority uint
@@ -184,7 +186,7 @@ func (p Proc) Stat() (ProcStat, error) {
 		&ignoreUint64,
 		&ignoreUint64,
 		&ignoreInt64,
-		&ignoreInt64,
+		&s.Processor,
 		&s.RTPriority,
 		&s.Policy,
 		&s.DelayAcctBlkIOTicks,