dep: update mdbook crate to 0.4.29

Author: ISSOtm

.github/workflows/build-and-deploy.yml

@@ -32,7 +32,7 @@ jobs:
     - name: Install mdbook
       uses: peaceiris/actions-mdbook@v1
       with:
-        mdbook-version: 0.4.21
+        mdbook-version: 0.4.29
 
     # FIXME: Keep this up to date
     - name: Install mdbook-linkcheck