fix(deps): update module sigs.k8s.io/controller-runtime to v0.21.0

Author: renovate[bot]

go.mod

@@ -11,7 +11,7 @@ require (
 	k8s.io/api v0.32.1
 	k8s.io/apimachinery v0.32.1
 	k8s.io/client-go v0.32.1
-	sigs.k8s.io/controller-runtime v0.20.2
+	sigs.k8s.io/controller-runtime v0.21.0
 	sigs.k8s.io/kind v0.29.0
 	sigs.k8s.io/kustomize/api v0.19.0
 	sigs.k8s.io/kustomize/kyaml v0.19.0