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/cespare/xxhash/v2/testall.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -eu -o pipefail
+
+# Small convenience script for running the tests with various combinations of
+# arch/tags. This assumes we're running on amd64 and have qemu available.
+
+go test ./...
+go test -tags purego ./...
+GOARCH=arm64 go test
+GOARCH=arm64 go test -tags purego