Add PyPi workflow.

.github/workflows/publish.yml

@@ -0,0 +1,28 @@
+name: Publish jpl-rosa to PyPI
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: '>=3.9 <4.0'
+
+    - name: Install dependencies
+      run: pip install setuptools wheel twine
+
+    - name: Build package
+      run: python setup.py sdist bdist_wheel
+
+    - name: Publish package
+      env:
+        TWINE_USERNAME: __token__
+        TWINE_PASSWORD: ${{ secrets.PYPI_API_TOKEN }}
+      run: twine upload dist/*