Set gh-action-pypi-publish to use release/v1 (#568)

master is deprecated, apparently

Author: msullivan

.github/workflows/release.yml

@@ -206,7 +206,7 @@ jobs:
         ls -al dist/
 
     - name: Upload to PyPI
-      uses: pypa/gh-action-pypi-publish@master
+      uses: pypa/gh-action-pypi-publish@release/v1
       with:
         user: __token__
         password: ${{ secrets.PYPI_TOKEN }}