Test deploy to TestPypi.

Author: janjezersek

.github/workflows/publish_to_pypi.yml

@@ -36,5 +36,6 @@ jobs:
       uses: pypa/gh-action-pypi-publish@release/v1
       with:
         user: __token__
-        password: ${{ secrets.PYPI_API_TOKEN }}
+        password: ${{ secrets.TEST_PYPI_API_TOKEN }}
         verbose: true
+        repository_url: https://test.pypi.org/legacy/