chore: add codeowners file

[Nihisil]

it will automatically assign us on PRs as reviewers, the file sorted alphabetically

[Apricot-S]

It seems that the current CODEOWNERS entries:

@Apricot-S
@Nihisil

do not work as intended, because CODEOWNERS requires each line to start with a path pattern.
Without a pattern, these lines are ignored by GitHub.

If the intention is to assign both users as code owners for all files, please update it to:

* @Apricot-S @Nihisil

Reference:
https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners

[Nihisil]

Interesting that GH says that file is valid:

but I changed it as you suggested