ci: skip existing distributions to avoid upload conflicts

Author: JoshuaWink

.github/workflows/manual-release-to-pypi.yml

@@ -65,6 +65,7 @@ jobs:
         user: __token__
         password: ${{ secrets.PYPI_TOKEN }}
         verbose: true
+        skip-existing: true
 
     - name: Create GitHub Release
       uses: actions/create-release@v1