ci: Publish to test.pypi.org on every commit against main.

Author: seifertm

.github/workflows/main.yml

@@ -183,10 +183,28 @@ jobs:
         name: release-notes.md
         path: release-notes.md
 
-  deploy:
-    name: Deploy
+  publish-test-pypi:
+    name: Publish packages to test.pypi.org
+    environment: release
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    needs: [lint, check]
+    runs-on: ubuntu-latest
+    permissions:
+      id-token: write
+    steps:
+    - name: Download distributions
+      uses: actions/download-artifact@v4
+      with:
+        name: dist
+        path: dist
+    - name: Upload to test.pypi.org
+      uses: pypa/gh-action-pypi-publish@76f52bc884231f62b9a034ebfe128415bbaabdfc  # v1.12.4
+      with:
+        repository-url: https://test.pypi.org/legacy/
+
+  publish-pypi:
+    name: Publish packages to pypi.org
     environment: release
-        # Run only on pushing a tag
     if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')
     needs: [lint, check, prepare-release-notes]
     runs-on: ubuntu-latest