Remove codeowners API calls

The API calls slow down the CI/CD pipelines.

Following the suggestion in handbook#170 (comment 1734770565)

I have no idea how to test this MR, or whether the syntax is correct. Starting new with Hugo Go templates. 😞

Edit: Figured it out. You can run Hugo with Docker in the theme directory, too.

docker run --rm -v ${PWD}:/src -p 1313 --name gl-hugo-exts hugomods/hugo:exts hugo server