Add pypi package workflow

.github/workflows/package.yml

@@ -0,0 +1,68 @@
+name: package
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  build_sdist:
+    name: Build SDist
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Build SDist
+        run: pipx run build --sdist
+
+      - name: Check metadata
+        run: pipx run twine check dist/*
+
+      - uses: actions/upload-artifact@v2
+        with:
+          path: dist/*.tar.gz
+
+
+  build_wheels:
+    name: Wheels on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: pypa/[email protected]
+        env:
+          CIBW_ARCHS_MACOS: auto universal2
+
+      - name: Verify clean directory
+        run: git diff --exit-code
+        shell: bash
+
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          path: wheelhouse/*.whl
+
+
+  upload_all:
+    name: Upload if release
+    needs: [build_wheels, build_sdist]
+    runs-on: ubuntu-latest
+    if: github.event_name == 'release' && github.event.action == 'published'
+
+    steps:
+      - uses: actions/setup-python@v2
+
+      - uses: actions/download-artifact@v2
+        with:
+          name: artifact
+          path: dist
+
+      - name: Deploy to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          user: __token__
+          password: ${{ secrets.PYPI_API_TOKEN }}