Add `--no-verify` to commit, push, etc

[ElPicador]

I'm using a lot of pre-commit/push hooks. And sometimes skipping them with a --no-verify can be useful.

I'm willing to implement this feature. Is it something you would be open to accept as a contribution? Any tips/comments on how to implement it?

[abhinav]

Hello! Yes, a contribution for this would be welcome.

In terms of implementation: The flag will be added to branchCreateCmd and the three commit subcommands amend, create, and split. All of these commands call git.Repository.Commit, which accepts a git.CommitRequest. We'll need a new field on that struct for this option, and in Repository.Commit we can convert it into a flag passed to Git.

Other minor notes about contributing:

• The project uses changie to track unreleased user-facing changes.
• After adding flags, run make generate inside the doc/ directory to update the CLI reference.
• Integration tests use testscript. See testdata/script/README for details. You should be able to adapt any of the existing tests to verify this behavior end-to-end.