Update mdBook version to 0.4.22

[tuscen]

I think we should also add cargo tracking to update mdbook

[karb0f0s]

I am not sure how to do it. Dependency page doesn't recognize it as an external dependency. We don't use it directly, we use external action to run it during the build process. We can run mdBook action with the latest available verison, but it would mean it could break any minute without notice.