Configure GitHub actions to publish packages (#418)

* Configure GitHub actions to publish packages

* Relax release restriction for testing

* Revert "Relax release restriction for testing"

This reverts commit 798b106 so releases
will be the only event which triggers a build.

Author: acdha

.github/workflows/pypi-release.yml

@@ -0,0 +1,38 @@
+name: "PyPI releases"
+
+on: release
+
+jobs:
+    build_sdist:
+        name: Build Python source distribution
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v3
+
+            - name: Build sdist
+              run: pipx run build --sdist
+
+            - uses: actions/upload-artifact@v3
+              with:
+                  path: dist/*.tar.gz
+
+    pypi-publish:
+        name: Upload release to PyPI
+        if: github.event_name == 'release' && github.event.action == 'published'
+        needs:
+            - build_sdist
+        runs-on: ubuntu-latest
+        environment:
+            name: pypi
+            url: https://pypi.org/p/pysolr
+        permissions:
+            id-token: write
+        steps:
+            - uses: actions/download-artifact@v3
+              with:
+                  # unpacks default artifact into dist/
+                  # if `name: artifact` is omitted, the action will create extra parent dir
+                  name: artifact
+                  path: dist
+            - name: Publish package distributions to PyPI
+              uses: pypa/gh-action-pypi-publish@release/v1