Make new org team codeowner

[infinisil]

Over time we should assign others, but for now this makes the most sense

[infinisil]

This is not a problem with this PR itself, but it's a good time to address it:

We wanted to switch to GitHub App authentication for the codeowners validation, which would work for https://github.com/mszostok/codeowners-validator, but not the custom script I wrote to check that everybody has write access (which I wrote because it's not supported by codeowners-validator), since the script relies on a GitHub token and it's non-trivial to authenticate as a GitHub App instead.

Well, instead of trying to hack around with more bash, I decided to implement this feature in codeowners-validator instead: mszostok/codeowners-validator#222 😄

[zimbatm]

:LGTM:

[zimbatm]

I think this will have to be force-merged due to the target_pull_request rule

[infinisil]

I'm not making use of my fix yet, I'll try that soon. Let's not merge until then :)

Edit:

• Use GitHub App for codeowner validation and remove hacky script #8

[infinisil]

Now that #8 is merged, this passes CI and is ready to be merged :)