CHANGES.rst: Fix version

[hugovk]

Summary of changes

Fix double version in changelog.

Pull Request Checklist

• Changes have tests
• News fragment added in changelog.d/.
  (See documentation for details)

[jaraco]

The change that introduced this error was 529419e, which was introduced by running tox -e finalize. It seems towncrier is no longer able to properly finalize the release, so while this change will address the symptom, the root cause, probably introduced in #2654, will still need to be addressed.