ci: fix checkout ref

Author: danielloader

.github/workflows/release.yml

@@ -17,6 +17,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+        with:
+          ref: ${{ github.head_ref }}
       - name: Install poetry
         run: pipx install poetry==${POETRY_VERSION}
       - name: Set up Python