Bump golang.org/x/mod from 0.26.0 to 0.28.0

Bumps [golang.org/x/mod](https://github.com/golang/mod) from 0.26.0 to 0.28.0.
- [Commits](golang/mod@v0.26.0...v0.28.0)

---
updated-dependencies:
- dependency-name: golang.org/x/mod
  dependency-version: 0.28.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

go.mod

@@ -1,5 +1,5 @@
 module github.com/prometheus/golang-builder
 
-go 1.23.0
+go 1.24.0
 
-require golang.org/x/mod v0.26.0
+require golang.org/x/mod v0.28.0

go.sum

@@ -1,2 +1,2 @@
-golang.org/x/mod v0.26.0 h1:EGMPT//Ezu+ylkCijjPc+f4Aih7sZvaAr+O3EHBxvZg=
-golang.org/x/mod v0.26.0/go.mod h1:/j6NAhSk8iQ723BGAUyoAcn7SlD7s15Dp9Nd/SfeaFQ=
+golang.org/x/mod v0.28.0 h1:gQBtGhjxykdjY9YhZpSlZIsbnaE2+PgjfLWUQTnoZ1U=
+golang.org/x/mod v0.28.0/go.mod h1:yfB/L0NOf/kmEbXjzCPOx1iK1fRutOydrCMsqRhEBxI=