A pull request authored with GITHUB_TOKEN never starts other workflows, so
the weekly acknowledgments PR never reported the checks branch protection
requires and could only land by bypassing it. The step now uses the
dedicated ACKNOWLEDGMENTS_TOKEN secret when it is set, and falls back to
GITHUB_TOKEN otherwise.
The contributor table also listed github-actions[bot]; bot accounts are
now filtered before the top 20 are taken (30 are fetched to keep 20).
Checked by running the script against the live API: the previous version
writes one github-actions row, this one writes none.
yhh