chore(deps): update dependency googlecontainertools/skaffold to v2.21.0 (#230)

Author: renovate[bot]

.github/workflows/test.yml

@@ -34,7 +34,7 @@ jobs:
             kubectl
             skaffold
           kubectl: v1.36.1 # renovate: datasource=github-releases depName=kubernetes/kubernetes
-          skaffold: v2.19.0 # renovate: datasource=github-releases depName=GoogleContainerTools/skaffold
+          skaffold: v2.21.0 # renovate: datasource=github-releases depName=GoogleContainerTools/skaffold
 
       - name: Setup k3sup
         env: