Add GitHub Actions workflow for PyPI publishing

Author: oliverchampion

.github/workflows/PyPi_installer.yml

@@ -0,0 +1,32 @@
+# Publishes to TestPyPI when you push a tag starting with "test-v"
+on:
+  push:
+    tags:
+      - "test-v*"
+
+# Publishes to real PyPI when you create a proper GitHub release
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - run: pip install build
+      - run: python -m build
+
+      - name: Publish to TestPyPI
+        if: startsWith(github.ref, 'refs/tags/test-v')
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          repository-url: https://test.pypi.org/legacy/
+
+      - name: Publish to PyPI
+        if: github.event_name == 'release'
+        uses: pypa/gh-action-pypi-publish@release/v1