Don't build dev docs for on release

.github/workflows/docs-python.yml

@@ -51,7 +51,7 @@ jobs:
         run: make html
 
       - name: Deploy Python docs for latest development version
-        if: ${{ github.ref_name == 'main' }}
+        if: github.event_name == 'push' && github.ref_name == 'main'
         uses: JamesIves/github-pages-deploy-action@v4
         with:
           folder: py-polars/docs/build/html