Use netlify action

.github/workflows/build_book.yaml

@@ -4,6 +4,9 @@ on:
 
 name: bookdown
 
+env:
+  isExtPR: ${{ github.event.pull_request.head.repo.fork == true }}
+
 jobs:
   build:
     runs-on: ubuntu-16.04
@@ -66,10 +69,18 @@ jobs:
         uses: actions/setup-node@v1
 
       - name: Deploy to Netlify
-        # NETLIFY_AUTH_TOKEN and NETLIFY_SITE_ID added in the repo's secrets
+        if: contains(env.isExtPR, 'false')
+        id: netlify-deploy
+        uses: nwtgck/actions-netlify@v1.1
+        with:
+          publish-dir: './_book'
+          production-branch: master
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          deploy-message:
+            'Deploy from GHA: ${{ github.event.pull_request.title || github.event.head_commit.message }} (${{ github.sha }})'
+          enable-pull-request-comment: false
+          enable-commit-comment: false
         env:
           NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}
           NETLIFY_SITE_ID: ${{ secrets.NETLIFY_SITE_ID }}
-        run: |
-          npm install netlify-cli -g
-          netlify deploy --prod --dir _book
+        timeout-minutes: 1