Fix github pages deployment

[Nashtare]

Adds a caching step to retrieve on the deployment phase, as the logs seem to indicate the data is missing:

  [INFO] copy /home/runner/work/zk_evm/zk_evm/book/book to /home/runner/actions_github_pages_1725975623120
  cp: no such file or directory: /home/runner/work/zk_evm/zk_evm/book/book/*
  cp: no such file or directory: /home/runner/work/zk_evm/zk_evm/book/book/.*

Tweaked deployment rule for testing temporarily

[Nashtare]

Ok caching seems to work fine with path specified, see https://0xpolygonzero.github.io/zk_evm/.