ci: add GitHub Actions workflow to build and deploy mdBook docs

Author: AliwiWalid

.github/workflows/deploy-mdbook.yml

@@ -0,0 +1,25 @@
+name: Deploy mdBook to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Install mdBook
+      run: cargo install mdbook
+
+    - name: Build the book
+      run: mdbook build docs
+
+    - name: Deploy to GitHub Pages
+      uses: peaceiris/actions-gh-pages@v3
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        publish_dir: ./docs/book