kubectl: add alias to list pods by namespace (#8604)

plugins/kubectl/kubectl.plugin.zsh

@@ -47,6 +47,9 @@ alias kdelp='kubectl delete pods'
 # get pod by label: kgpl "app=myapp" -n myns
 alias kgpl='kgp -l'
 
+# get pod by namespace: kgpn kube-system"
+alias kgpn='kgp -n'
+
 # Service management.
 alias kgs='kubectl get svc'
 alias kgsa='kubectl get svc --all-namespaces'