build(deps): bump github.com/prometheus/alertmanager (thanos-io#6671)

Bumps [github.com/prometheus/alertmanager](https://github.com/prometheus/alertmanager) from 0.25.0 to 0.25.1.
- [Release notes](https://github.com/prometheus/alertmanager/releases)
- [Changelog](https://github.com/prometheus/alertmanager/blob/v0.25.1/CHANGELOG.md)
- [Commits](prometheus/alertmanager@v0.25.0...v0.25.1)

---
updated-dependencies:
- dependency-name: github.com/prometheus/alertmanager
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

go.mod

@@ -56,7 +56,7 @@ require (
 	github.com/opentracing/opentracing-go v1.2.0
 	github.com/pkg/errors v0.9.1
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/prometheus/alertmanager v0.25.0
+	github.com/prometheus/alertmanager v0.25.1
 	github.com/prometheus/client_golang v1.16.0
 	github.com/prometheus/client_model v0.4.0
 	github.com/prometheus/common v0.44.0

go.sum

@@ -781,8 +781,8 @@ github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndr
 github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c h1:ncq/mPwQF4JjgDlrVEn3C11VoGHZN7m8qihwgMEtzYw=
 github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c/go.mod h1:OmDBASR4679mdNQnz2pUhc2G8CO2JrUAVFDRBDP/hJE=
 github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
-github.com/prometheus/alertmanager v0.25.0 h1:vbXKUR6PYRiZPRIKfmXaG+dmCKG52RtPL4Btl8hQGvg=
-github.com/prometheus/alertmanager v0.25.0/go.mod h1:MEZ3rFVHqKZsw7IcNS/m4AWZeXThmJhumpiWR4eHU/w=
+github.com/prometheus/alertmanager v0.25.1 h1:LGBNMspOfv8h7brb+LWj2wnwBCg2ZuuKWTh6CAVw2/Y=
+github.com/prometheus/alertmanager v0.25.1/go.mod h1:MEZ3rFVHqKZsw7IcNS/m4AWZeXThmJhumpiWR4eHU/w=
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829/go.mod h1:p2iRAGwDERtqlqzRXnrOVns+ignqQo//hLXqYxZYVNs=
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=