ci: use github-actions[bot] as author for weekly lockfile commits

The peter-evans/create-pull-request action defaults author to
${{ github.actor }}. For scheduled workflows, GitHub assigns this to
a human user (the schedule owner), causing weekly dependency update
commits to be incorrectly attributed to a maintainer rather than the
bot.

Github-Issue: #2043

Author: maxisbey

.github/workflows/weekly-lockfile-update.yml

@@ -32,6 +32,7 @@ jobs:
         uses: peter-evans/create-pull-request@c0f553fe549906ede9cf27b5156039d195d2ece0 # v7
         with:
           commit-message: "chore: update uv.lock with latest dependencies"
+          author: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
           title: "chore: weekly dependency update"
           body-path: pr_body.md
           branch: weekly-lockfile-update