Test runner doesn't commit snapshots on PRs issued by non-collaborators

[fmaclen]

We are currently using this Github action: https://github.com/ad-m/github-push-action

When a contributor is creating a PR and tests are run on that branch, the action is unable to commit the updated snapshots: https://github.com/fmaclen/hollama/actions/runs/11031748176/job/30639158719

I think there is a miss-understanding on how the credentials are set, right now we are using a Github Personal Access Token but those appear to be invalid when the tests are run on a non-collaborator branch.

Maybe we should use GITHUB_TOKEN instead of a PAT.