Bump mdbook version

0.4.5 is ancient. Use the latest and greatest version.

Signed-off-by: Stephen Finucane <[email protected]>

Author: stephenfin

versions.mk

@@ -12,6 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-MDBOOK_VERSION := v0.4.5
+MDBOOK_VERSION := v0.4.35
 PLANTUML_VERSION := 1.2022.6
 GH_VERSION := 1.2.0