chore: pin create-pull-request action to commit hash

Author: maxisbey

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

@@ -29,7 +29,7 @@ jobs:
           echo '```' >> pr_body.md
 
       - name: Create pull request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@22a9089034f40e5a961c8808d113e2c98fb63676 # v7
         with:
           commit-message: "chore: update uv.lock with latest dependencies"
           title: "chore: weekly dependency update"