add release workflow

.github/workflows/release.yaml

@@ -0,0 +1,38 @@
+name: Release to PyPI
+on:
+  release:
+    types: [published, edited]
+jobs:
+  pypi:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: extractions/setup-just@v1
+      - name: Install poetry
+        run: pipx install poetry
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+          cache: 'poetry'
+
+      - run: poetry config pypi-token.pypi "${{ secrets.PYPI_API_KEY }}"
+      - name: install twine
+        run: |
+          pip install twine
+
+      - name: download release
+        run: |
+          tag='${{ github.ref }}'
+          tag="${tag/refs\/tags\//}"
+          mkdir dist
+          cd dist
+          gh release download "$tag" -p 'extism-*'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: upload release
+        run: |
+          twine upload dist/*
+        env:
+          TWINE_USERNAME: __token__
+          TWINE_PASSWORD: ${{ secrets.PYPI_API_KEY }}

README.md

@@ -1,3 +1,18 @@
 # Extism Python Host SDK
 
-See [https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/](https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/).
+See [https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/](https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/).
+
+
+## Development
+
+### Release workflow
+
+1. Create a semver-formatted git tag (`git tag v1.0.0`).
+2. Push that tag to the repository (`git push origin v1.0.0`.)
+3. Wait for [the Build workflow to run](https://github.com/extism/python-sdk/actions/workflows/build.yaml).
+4. Once the build workflow finishes, go to the [releases](https://github.com/extism/python-sdk/releases) page. You should
+   see a draft release.
+5. Edit the draft release. Publish the release.
+6. Wait for [the Release workflow to run](https://github.com/extism/python-sdk/actions/workflows/release.yaml).
+7. Once the release workflow completes, you should be able to `pip install extism==${YOUR_TAG}` from PyPI.
+