Revisit automerge of Dependabot PRs

[jenstroeger]

Automatically merging Dependabot PRs works by commenting on a PR:

python-package-template/.github/workflows/dependabot-automerge.yaml

Line 18 in 152e6ad

run: gh pr comment --body "@dependabot squash and merge" "$PR_URL"

However:

with the announcement here.