Support rubocop 0.53.0

[amckinnell]

This is a straightforward extension of the current scheme for handling different versions of rubocop: add another configuration file to handle the cop that was renamed as part of the rubocop 0.53.0 release.

This change works just fine for my situation. Looking at the issues and pull requests it most likely will not suit everyone's needs :)

[olliebennett]

I think this is a good candidate to merge, and a good approach to resolving these compatibility problems long-term.

I think the requirements are;

• The app "just works", without users needing to override or make decisions about the RuboCop rules they want (especially if they don't use RuboCop in their project already).
• Maintain a (good) relaxed rubocop dependency in this gem's gemspec, to avoid forcing people to upgrade / downgrade.

Extra nice-to-haves are:

• A way to customise (or even disable Don't run rubocop on schema dumping #30) the RuboCop behaviour if desired.

The change (and approach) proposed in this PR meets the two basic requirements above, but not the "nice-to-have"; in future, if/when a broader decision is made about how to configure/override the behaviour of RuboCop, the logic here can be a fallback and default behaviour.

There's related discussion here: #27 and #25

[DamienMetzger]

👍

[bak1an]

Thanks @amckinnell !

Similar change has been merged in #33 so I am closing this.