chore(deps): bump k8s.io/client-go from 0.20.5 to 0.21.0

Bumps [k8s.io/client-go](https://github.com/kubernetes/client-go) from 0.20.5 to 0.21.0.
- [Release notes](https://github.com/kubernetes/client-go/releases)
- [Changelog](https://github.com/kubernetes/client-go/blob/master/CHANGELOG.md)
- [Commits](https://github.com/kubernetes/client-go/compare/v0.20.5...v0.21.0)

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

go.mod

@@ -72,7 +72,7 @@ require (
 	k8s.io/api v0.20.5
 	k8s.io/apiextensions-apiserver v0.20.2 // indirect
 	k8s.io/apimachinery v0.20.5
-	k8s.io/client-go v0.20.5
+	k8s.io/client-go v0.21.0
 	k8s.io/klog/v2 v2.5.0 // indirect
 	k8s.io/kube-openapi v0.0.0-20210113233702-8566a335510f // indirect
 	sigs.k8s.io/controller-runtime v0.8.1