[CI] Fix condition for cleaning up previews (#82)

This wasn't running on PR closed but on schedule/workflow dispatch.

Author: giordano

.github/workflows/DocPreviewsCleanup.yml

@@ -25,12 +25,11 @@ jobs:
           ref: gh-pages
       - name: Delete preview and history + push changes
         run: |
-          preview_directory=previews/PR${{ github.event.number }}
-          if [[ -d "${preview_directory}" ]]; then
+          if [[ -d previews ]]; then
             git config user.name "${{github.actor}}"
             git config user.email "${{github.actor_id}}+${{github.actor}}@users.noreply.github.com"
-            git rm -rf "${preview_directory}"
-            git commit -m 'Cleanup docs for PR #${{ github.event.number }}'
+            git rm -rf previews/
+            git commit -m 'Delete previews directory'
             git branch gh-pages-new $(echo "Delete history" | git commit-tree HEAD^{tree})
-            git push --force origin gh-pages-new:gh-pages
+            git push --force-with-lease origin gh-pages-new:gh-pages
           fi