Insert a newline at EOF of CHANGELOG.md

This commit fixes the folowing CI failure.

```console
% bundle exec rake

(snip)

==> Failures

  1) RuboCop Project changelog has newline at end of file
     Failure/Error: expect(changelog.end_with?("\n")).to be true

       expected true
            got false
     # ./spec/project_spec.rb:91:in `block (3 levels) in
            <top (required)>'
     # tasks/spec_runner.rake:67:in `run_worker'
     # tasks/spec_runner.rake:27:in `block in run_specs'
     # tasks/spec_runner.rake:41:in `with_encoding'
     # tasks/spec_runner.rake:25:in `run_specs'
     # tasks/spec_runner.rake:112:in `block in <top (required)>'
```

https://circleci.com/gh/rubocop-hq/rubocop/48849

CHANGELOG.md

@@ -3951,4 +3951,4 @@
 [@Blue-Pix]: https://github.com/Blue-Pix
 [@diachini]: https://github.com/diachini
 [@Mange]: https://github.com/Mange
-[@jmanian]: https://github.com/jmanian
+[@jmanian]: https://github.com/jmanian