revet GitHub action change for krew (#1484)

Signed-off-by: Shuting Zhao <shutting06@gmail.com>

.github/workflows/krew.yaml

@@ -1,8 +1,10 @@
 name: release kyverno-cli plugin
 on:
-  release:
-    types:
-      - published
+  push:
+    tags:
+      - 'v*'
+      - '!v*-rc*'
+
 jobs:
   release-cli-via-krew:
     runs-on: ubuntu-latest
@@ -14,5 +16,4 @@ jobs:
         run: git fetch --prune --unshallow
 
       - name: Update new version in krew-index
-        if: "!github.event.release.prerelease"
         uses: rajatjindal/krew-release-bot@v0.0.38