ci: grant workflows: write to patchloom-release GitHub App (for auto-merge on workflow edits)

[SebTardif]

PR #146 (and future PRs touching .github/workflows/) caused auto-approve to fail with:

'refusing to allow a GitHub App to create or update workflow ... without workflows permission'

The App (patchloom-release, client Iv23liXmsJgQyVZfTMGk) currently has only contents/pull_requests/issues.

Grant 'workflows: write' via https://github.com/organizations/patchloom/settings/apps/patchloom-release/permissions then accept the update at org installations page.

This is required per GitHub rules when App token does auto-merge on PRs that would modify workflow files.

[SebTardif]

Handled with code workaround in auto-approve.yml: skip --auto-merge step if PR changes .github/workflows/* files. This prevents the permission error without requiring the grant (though granting workflows:write on the App is still recommended for full auto-merge support on such PRs).

Workaround PR merged. See merged #152.