PHPCS/WPCS: git pull --no-edit if on master branch

I think this change should be made to other projects that VVV is cloning with Git and keeping up to date. If the user has checked out a branch other than master, than it is likely they are doing some development and don't want their feature branch to be automatically updated without manually requesting this. Furthermore, even if on the `master` branch and they've added commits on a fork, then the use of `--rebase` is a problem because it will rewrite the history and will break subsequent pushes to a fork. Therefore, it is better to let `git pull` add a merge commit so that the commits are not rewritten.