Fix a build error

This commit fixes the following build error.

```console
% bundle exec rspec ./spec/project_spec.rb:202
Run options: include {:focus=>true, :locations=>{"./spec/project_spec.rb"=>[202]}}

Randomized with seed 14569
F

Failures:

  1) RuboCop Project Changelog entry contributor name has a unique
  contributor name
       Failure/Error: expect(contributor_names.uniq.size).to eq
       contributor_names.size

expected: 581
got: 580

(compared using ==)
     Shared Example Group: "has Changelog format" called from
     ./spec/project_spec.rb:234
          # ./spec/project_spec.rb:202:in `block (5 levels) in
          <top (required)>'

Finished in 0.01846 seconds (files took 1.27 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./spec/project_spec.rb:201 # RuboCop Project Changelog entry
contributor name has a unique contributor name

Randomized with seed 14569
```

CHANGELOG.md

@@ -6317,5 +6317,4 @@
 [@zachahn]: https://github.com/zachahn
 [@kaitielth]: https://github.com/kaitielth
 [@j-miyake]: https://github.com/j-miyake
-[@kaitielth]: https://github.com/kaitielth
 [@FnControlOption]: https://github.com/FnControlOption