Add manual workflow to publish to TestPyPI

.github/workflows/test-publish.yaml

@@ -0,0 +1,32 @@
+---
+name: Publish test version to TestPyPI
+
+on:
+  workflow_dispatch:
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    environment: testpypi
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '${{ env.DEFAULT_PYTHON }}'
+
+      - name: Build
+        run: |
+          # Cheat
+          sed -i '/\[tool.setuptools_scm\]/ s/$/\nlocal_scheme = "no-local-version"/' pyproject.toml
+          pip install build
+          python3 -m build
+      - name: Publish package distributions to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          repository-url: https://test.pypi.org/legacy/