feat: add /update-snapshot comment trigger to update_snapshot workflow

Author: konokenj

.github/workflows/update_snapshot.yml

@@ -4,15 +4,23 @@ on:
   workflow_dispatch:
   push:
     branches:
-       - 'dependabot/**'
+      - 'dependabot/**'
+  issue_comment:
+    types: [created]
 
 permissions:
   contents: write
 jobs:
   update:
+    if: >
+      github.event_name == 'push' ||
+      github.event_name == 'workflow_dispatch' ||
+      (github.event.issue.pull_request && contains(github.event.comment.body, '/update-snapshot'))
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
+        with:
+          ref: ${{ github.event_name == 'issue_comment' && format('refs/pull/{0}/head', github.event.issue.number) || '' }}
       - name: Use Node.js
         uses: actions/setup-node@v6
         with: