ci: don't check repository_owner

[0xda157]

follow up to https://github.com/nix-community/stylix/pull/1420, cc @MattSturgeon

Things done

• [ ] Tested locally
• [ ] Tested in testbed
• [x] Commit message follows commit convention
• [ ] Fits style guide
• [ ] Respects license of any existing code used

Notify maintainers