Do not force push in doc preview cleanup (#2794)

Author: mortenpi

.github/workflows/ClearPreview.yml

@@ -19,8 +19,7 @@ jobs:
               git config user.email "[email protected]"
               git rm -rf "previews/PR$PRNUM"
               git commit -m "delete preview"
-              git branch gh-pages-new $(echo "delete history" | git commit-tree HEAD^{tree})
-              git push --force origin gh-pages-new:gh-pages
+              git push origin gh-pages:gh-pages
             fi
         env:
             PRNUM: ${{ github.event.number }}