tests(docs.yml): Update docs should only happens in master branch

Author: jcs090218

.github/workflows/docs.yml

@@ -8,6 +8,9 @@ on:
     paths:
       - '**.yml'
       - docs/**
+  pull_request:
+    branches:
+      - master
   workflow_dispatch:
 
 concurrency:
@@ -34,7 +37,7 @@ jobs:
         npm run build
 
     - name: Check out GitHub page repo
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       with:
         repository: emacs-eask/emacs-eask.github.io
         path: emacs-eask.github.io
@@ -46,6 +49,7 @@ jobs:
 
     # TODO: Generate better commit message
     - name: Publish doc artifacts
+      if: github.ref == 'refs/heads/master'
       run: |
         git config user.name github-actions
         git config user.email github-actions@github.com