squash upgrade dep commits

Author: tschaume

.github/workflows/upgrade_dependencies.yml

@@ -68,6 +68,8 @@ jobs:
           git checkout -b auto-dependency-upgrades
           git branch -r | grep auto-dependency-upgrades- | xargs -I {} git merge {}
           git rebase ${GITHUB_REF##*/}
+          git reset $(git merge-base ${GITHUB_REF##*/} HEAD)
+          git commit -a -m "auto dependency upgrades"
           git push -f origin auto-dependency-upgrades
           git branch -r | grep auto-dependency-upgrades- | cut -d/ -f2 | xargs -I {} git push origin :{}
       - name: Open pull request if needed