Bump golang.org/x/mod from 0.14.0 to 0.15.0

Bumps [golang.org/x/mod](https://github.com/golang/mod) from 0.14.0 to 0.15.0.
- [Commits](https://github.com/golang/mod/compare/v0.14.0...v0.15.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -5,7 +5,7 @@ go 1.20
 require (
 	github.com/gorilla/mux v1.8.1
 	github.com/stretchr/testify v1.8.4
-	golang.org/x/mod v0.14.0
+	golang.org/x/mod v0.15.0
 	gopkg.in/yaml.v2 v2.4.0
 )