fix(ci): restrict last_modified updates to FAQ files on master PRs

Author: lyzhang0113

.github/workflows/update-last-modified.yml

@@ -4,19 +4,18 @@ on:
   pull_request:
     branches:
       - master
-      - main
     types:
       - opened
       - synchronize
       - reopened
     paths:
-      - "_articles/**/*.md"
+      - "_articles/faq/*.md"
 
 permissions:
   contents: write
 
 jobs:
-  update-on-main-pr:
+  update-on-master-pr:
     if: github.actor != 'github-actions[bot]' && github.event.pull_request.head.repo.full_name == github.repository
     runs-on: ubuntu-latest
     steps:
@@ -35,7 +34,7 @@ jobs:
           git fetch origin "${{ github.event.pull_request.base.ref }}"
 
           git diff --name-only "origin/${{ github.event.pull_request.base.ref }}"...HEAD \
-            | grep -E '^_articles/.+\.md$' \
+            | grep -E '^_articles/faq/[^/]+\.md$' \
             | sort -u > changed_files.txt || true
 
           count="$(wc -l < changed_files.txt | tr -d ' ')"
@@ -83,6 +82,9 @@ jobs:
 
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
-          git add _articles
+          while IFS= read -r file; do
+            [[ -f "$file" ]] || continue
+            git add "$file"
+          done < changed_files.txt
           git commit -m "chore: update last_modified timestamps"
           git push origin HEAD:${{ github.event.pull_request.head.ref }}