chore(ci): verify tap in PR

[YOU54F]

Trying to fix the verify tap step when PR's are raised.

-brew pull was deprecated and replaced by hub checkout https://brew.sh/2020/06/11/homebrew-2.4.0/

• need to update the pull request ref to use version/ prefix to ensure correct PR checked out - https://hub.github.com/hub-checkout.1.html
• some audit failures

pact-ruby-standalone:
  * 2: col 3: Description is too long. It should be less than 80 characters. The current length is 94.
  * Stable: version 1.91.0 is redundant with version scanned from URL
  * Libraries were compiled with a flat namespace.
    This can cause linker errors due to name collisions, and
    is often due to a bug in detecting the macOS version.
      /opt/homebrew/Cellar/pact-ruby-standalone/1.91.0/lib/ruby/lib/libyaml-0.2.dylib

Have fixed

• Description
• Version brew audit: Is "#{version}" redundant? Homebrew/legacy-homebrew#32540

That third is a bit different Libraries were compiled with a flat namespace and can't find much on info on it

• Libraries were compiled with a flat namespace? Homebrew/discussions#4091