Fix name of PyPI token variable

The changed line accesses the environment variable "PYPI_TOKEN" that's initialized from the secret further up.
When the secret name was changed, we had accidentally changed the name of the environment variable only in this line.

Author: michaelosthege

.github/workflows/release.yml

@@ -39,7 +39,7 @@ jobs:
     - name: Publish to PyPI
       run: |
         twine check dist/*
-        twine upload --repository pypi --username __token__ --password ${PYPI_TOKEN_PYMC} dist/*
+        twine upload --repository pypi --username __token__ --password ${PYPI_TOKEN} dist/*
   test-install-job:
     needs: release-job
     runs-on: ubuntu-latest