[Hooks] Add fixture for the merge commit case.
[Hooks] Do not process merge commits.
[Rubocop] Silence Rubocop.

Please put down your weapon. You have 20 seconds to comply.
You now have 15 seconds to comply.
You are in direct violation of Penal Code 1.13, Section 9.
You have 5 seconds to comply.
Four... three... two... one... I am now authorized to use physical force!