Add workflow for publishing to PyPI

.github/workflows/publish-to-pypi.yml

@@ -0,0 +1,30 @@
+name: Upload Python Package to PyPI when a Release is Created
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  pypi-publish:
+    name: Publish release to PyPI
+    runs-on: ubuntu-latest
+    environment:
+      name: pypi
+      url: https://pypi.org/p/diffopt
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install setuptools wheel setuptools-scm
+      - name: Build package
+        run: |
+          python setup.py sdist bdist_wheel
+      - name: Publish package distributions to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1