Fix typo in CHANGELOG

[yujideveloper]

I fix typo of PR link in CHANGELOG

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Before submitting the PR make sure the following are checked:

• 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.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[koic]

Oops, this is my mistake.

This repository tests the changelog format, please remove [ci skip] from the commit message.
And can you do the same update for v0.81.0.md?
https://github.com/rubocop-hq/rubocop/blob/master/relnotes/v0.81.0.md

[yujideveloper]

Hi, @koic

Thanks feedback.

I fixed relnotes/v0.81.0.md as same as CHANGELOG.
And I removed [ci skip] from commit message.

[koic]

Thanks for fixing!