add config for gemini reviews

[xsuchy]

I want to try the Gemini review in this repo. I've got good feedback on it from the Packit team.
If no one objects, I will enable
https://github.com/marketplace/gemini-code-assist

I treat it as an experiment. If that makes more noise than help, we can disable it later.

[praiskup]

-1 for giving it write access to anything. I have nothing against read-only access.

[praiskup]

Do we have it enabled anywhere else to better understand the benefits?

[xsuchy]

Packit uses it. You can see e.g., this PR packit/ai-workflows#103 (see outdated comments)

[xsuchy]

Where do you see that it has write access. AFAIK it should only put comments in PR.

[praiskup]

I haven't checked, I'm just guessing. If it gets read only access, and rights for opening PRs and comments, it seems safe (OTOH, not sure if this isn't implicit). It would be nice to review the granted permissions, otherwise looks OK to me.
Would be nice to inform random contributors that those comments are not a big deal.

[praiskup]

We've checked it has only read-only access - but we don't have access to rpm-software-management org admins. https://github.com/rpm-software-management/org-admin/issues