Add kustomize/plugin config location.

@@ -41,6 +41,7 @@ data:
   run-helmfile: |
     #!/bin/sh
     set -ex
+    mkdir -p $HOME/.config/kustomize/plugin
     helm plugin install https://github.com/mumoshu/helm-x
     helm plugin install https://github.com/databus23/helm-diff
     helm plugin install https://github.com/aslafy-z/helm-git.git