build(deps): bump golang.org/x/oauth2 from 0.20.0 to 0.21.0

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.20.0 to 0.21.0.
- [Commits](https://github.com/golang/oauth2/compare/v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: golang.org/x/oauth2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -28,7 +28,7 @@ require (
 	go.uber.org/automaxprocs v1.5.3
 	golang.org/x/crypto v0.24.0
 	golang.org/x/net v0.26.0
-	golang.org/x/oauth2 v0.20.0
+	golang.org/x/oauth2 v0.21.0
 	golang.org/x/sync v0.7.0
 	golang.org/x/sys v0.21.0
 	golang.org/x/term v0.21.0