Make Rails/EagerEvaluationLogMessage enabled by default

[Uaitt]

On issue #1355 we had some discussions about the Rails/EagerEvaluationLogMessage cop. In particular, @Earlopain did some useful benchmarks of some possible scenarios.

After seeing the benchmarks, it's pretty obvious to note that offenses that this cop reports (that is, interpolated strings passed to Rails.logger.debug ) are very slow compared to the form that the cop allows (that is, blocks passed to Rails.logger.debug).

With that being said, considering that the performance hit is now clear between the 2 forms, we might as well enable this cop by default.

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Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.

[Earlopain]

Thanks, but cops aren't enabled in minor releases. If a user wants it right now, they must either use NewCops: enable or enable it manually. See https://docs.rubocop.org/rubocop/versioning.html#pending-cops

[koic]

I'm going to close this proposal because newly introduced rules are not enabled by default until a major version update. Thank you.