Clarify annotations behavior

[kema-dev]

Welcome

• Yes, I understand that the GitHub action repository is not the repository of golangci-lint itself.
• Yes, I've searched similar issues on GitHub and didn't find any.

Your feature request related to a problem? Please describe.

The readme here suggests that checks: write permissions are needed for annotation to work. I do not think this is true.
As this line suggests, annotation are made from problem matchers, as documented here.
As far as I could test, such annotation-from-logs does not need permissions to show in PR changed files.
The checks / problem matchers / annotation on GitHub looks kinda misleading to me, let me know if I missed something

Describe the solution you'd like.

Remove the checks: write mention in the readme

Describe alternatives you've considered.

#5, but needs some more code

Additional context.

No response