Fix an error when using inherit_gem: rubocop-rspec: config/default.yml

[ydah]

Fix: #1698 (comment)

Once we delete it from config/obsoletion.yml, because it is an error if it is a split.

How about proceeding as follows?

• Remove the configuration from config/obsoletion.yml once, since split would result in an error. (Patch version release)
• Release a version that warns if RSpec/FilePath is used (Next and subsequent releases)
• Remove RSpec/FilePath in the next major version update

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Before submitting the PR make sure the following are checked:

• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• [-] Added tests.
• Updated documentation.
• Added an entry to the CHANGELOG.md if the new code introduces user-observable changes.
• The build (bundle exec rake) passes (be sure to run this locally, since it may produce updated documentation that you will need to commit).

[pirj]

See the discussion in the comment thread.