Bump gitlab-styles to v13

In order to keep our coding conventions within gitlab-qa consistent with the rest of the gitlab codebase we should ensure we keep the rubocop rules in alignment.

As there is a huge number of style changes, lets consider breaking this into a couple of parts to update as much of the codebase as we can in a series of smaller more manageable MRs prior to doing a final MR to actually bump the changes.
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