[BUG] [Ruby] Rubocop deprecation error

Created by: rhuanbarreto

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?

Description

If you run rubocop on the generated client it gives an error:

Error: The Layout/Tab cop has been renamed to Layout/IndentationStyle. (obsolete configuration found in clients/ruby/.rubocop.yml, please update it)

Rubocop version: 0.84.0

openapi-generator version

4.3.1

Suggest a fix

A PR is being opened.