make keepalive push to branch keepalive

Author: bgctw

.github/workflows/CompatHelper.yml

@@ -43,6 +43,8 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           COMPATHELPER_PRIV: ${{ secrets.DOCUMENTER_KEY }}
           # COMPATHELPER_PRIV: ${{ secrets.COMPATHELPER_PRIV }}
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
+        with:
+          ref: 'keepalive'      # The branch, tag or SHA to checkout. 
       - uses: bgctw/keepalive-workflow@master