Update workflow

.github/workflows/book.yml

@@ -3,9 +3,12 @@ name: zkEVM mdbook
 on:
   push:
     branches: [develop, main]
+  pull_request:
+    branches:
+      - "**"
 
 jobs:
-  deploy:
+  build:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -26,9 +29,18 @@ jobs:
           command: install
           args: mdbook-katex mdbook-bib mdbook-mermaid
 
+      - name: Initialize mermaid preprocessor
+        run: mdbook-mermaid install book
+
       - name: Build book
         run: mdbook build book
 
+  deploy:
+    if: github.event_name == 'push' && (github.ref == 'refs/heads/main' || github.ref == 'refs/heads/develop')
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - uses: actions/checkout@v3
       - name: Deploy to GitHub Pages
         uses: peaceiris/actions-gh-pages@v3
         with:

book/.gitignore

@@ -3,4 +3,4 @@ book
 # Mermaid initialization files
 # Obtained with `mdbook-mermaid install book`.
 mermaid-init.js
-mermaid.min.js
+mermaid.min.js