*: Bump k8s.io/kube-aggregator from 0.21.3 to 0.28.2

Bumps [k8s.io/kube-aggregator](https://github.com/kubernetes/kube-aggregator) from 0.21.3 to 0.28.2.
- [Commits](kubernetes/kube-aggregator@v0.21.3...v0.28.2)

---
updated-dependencies:
- dependency-name: k8s.io/kube-aggregator
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -19,7 +19,7 @@ require (
 	k8s.io/apimachinery v0.28.2
 	k8s.io/cli-runtime v0.28.2
 	k8s.io/client-go v0.28.2
-	k8s.io/kube-aggregator v0.21.3
+	k8s.io/kube-aggregator v0.28.2
 	k8s.io/kubectl v0.28.2
 	sigs.k8s.io/yaml v1.3.0
 )