Update mdbook

Author: ehuss

.github/workflows/bindgen.yml

@@ -164,6 +164,6 @@ jobs:
       # NOTE(emilio): Change deploy-book as well if you change this.
       - name: Test book
         run: |
-          curl -L https://github.com/rust-lang/mdBook/releases/download/v0.4.4/mdbook-v0.4.4-x86_64-unknown-linux-gnu.tar.gz | tar xz
+          curl -L https://github.com/rust-lang/mdBook/releases/download/v0.4.5/mdbook-v0.4.5-x86_64-unknown-linux-gnu.tar.gz | tar xz
           ./mdbook build book
           ./mdbook test book

.github/workflows/deploy-book.yml

@@ -22,7 +22,7 @@ jobs:
 
       - name: Test book
         run: |
-          curl -L https://github.com/rust-lang/mdBook/releases/download/v0.4.4/mdbook-v0.4.4-x86_64-unknown-linux-gnu.tar.gz | tar xz
+          curl -L https://github.com/rust-lang/mdBook/releases/download/v0.4.5/mdbook-v0.4.5-x86_64-unknown-linux-gnu.tar.gz | tar xz
           ./mdbook build book
           ./mdbook test book