Add github actions upload to PyPI action

.github/workflows/release.yml

@@ -0,0 +1,80 @@
+name: PyPI release
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    name: Build source distribution
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.8
+      - name: Build the sdist and the wheel
+        run: |
+          pip install build
+          python -m build
+      - name: Check the sdist installs and imports
+        run: |
+          mkdir -p test-sdist
+          cd test-sdist
+          python -m venv venv-sdist
+          venv-sdist/bin/python -m pip install ../dist/CausalPy*.tar.gz
+          # check import
+          venv-sdist/bin/python -c "import causalpy; assert causalpy.__version__ == '${{  github.ref_name }}'"
+      - name: Check the bdist installs and imports
+        run: |
+          mkdir -p test-bdist
+          cd test-bdist
+          python -m venv venv-bdist
+          venv-bdist/bin/python -m pip install ../dist/CausalPy*.whl
+          # check import
+          venv-bdist/bin/python -c "import causalpy; assert causalpy.__version__ == '${{  github.ref_name }}'"
+      - uses: actions/upload-artifact@v3
+        with:
+          name: artifact
+          path: dist/*
+  test:
+    name: Upload to Test PyPI
+    needs: [build]
+    runs-on: ubuntu-latest
+    if: github.event_name == 'release' && github.event.action == 'published'
+    steps:
+      - uses: actions/download-artifact@v3
+        with:
+          name: artifact
+          path: dist
+      - uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          skip_existing: true
+          user: __token__
+          password: ${{ secrets.TEST_PYPI_API_TOKEN }}
+          repository_url: https://test.pypi.org/legacy/
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.8
+      - name: Test pip install from test.pypi
+        run: |
+          python -m venv venv-test-pypi
+          venv-test-pypi/bin/python -m pip install --index-url https://test.pypi.org/simple/ causalpy
+          # check import
+          venv-test-pypi/bin/python -c "import causalpy; assert causalpy.__version__ == '${{  github.ref_name }}'"
+
+  publish:
+    name: Upload release to PyPI
+    needs: [build, test]
+    runs-on: ubuntu-latest
+    if: github.event_name == 'release' && github.event.action == 'published'
+    steps:
+      - uses: actions/download-artifact@v3
+        with:
+          name: artifact
+          path: dist
+      - uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          user: __token__
+          password: ${{ secrets.PYPI_API_TOKEN }}