Fix wrong version numbers for PyPI releases (#216)

For test releases to TestPyPI we have to edit the setuptools_scm
configuration to produce valid version numbers. But it turns out that
this breaks the number for actual releases. To fix it, only edit the
configuration on non-release builds.

.github/workflows/deploy.yml

@@ -60,13 +60,16 @@ jobs:
       - name: List installed packages
         run: python -m pip freeze
 
-      - name: Build source and wheel distributions
+      - name: Don't use local version numbers for TestPyPI uploads
+        if: github.event_name != 'release'
         run: |
           # Change setuptools-scm local_scheme to "no-local-version" so the
           # local part of the version isn't included, making the version string
           # compatible with Test PyPI.
           sed --in-place "s/node-and-date/no-local-version/g" setup.py
-          python setup.py sdist bdist_wheel
+
+      - name: Build source and wheel distributions
+        run: python setup.py sdist bdist_wheel
           echo ""
           echo "Generated files:"
           ls -lh dist/