💚 Update mdBook version in workflow

Author: phoenixr-codes

.github/workflows/website.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v2
         with:
-          mdbook-version: "0.4.42"
+          mdbook-version: "0.4.51"
       - name: Download mdbook-admonish
         run: |
           mkdir ${{ env.TARGET }}