fix(ci): auto-generate GitHub release notes on publish

gh release create was passed --notes "", publishing every release with
an empty body and requiring a manual gh release edit afterward (hit us
on v1.5.2). Use --generate-notes so GitHub fills in notes from merged
PRs since the previous tag.

Author: firstmate crewmate

.github/workflows/python-publish.yml

@@ -72,7 +72,7 @@ jobs:
           gh release create
           '${{ github.ref_name }}'
           --repo '${{ github.repository }}'
-          --notes ""
+          --generate-notes
       - name: Upload artifacts to GitHub Release
         env:
           GITHUB_TOKEN: ${{ github.token }}