app.ini.tmpl changed in "BREAKING CHANGE: remove forgejo" but the config version
stayed at v22. Swarm configs are immutable, so upgrading an existing deployment
aborts:
FATA failed to update config <stack>_app_ini_v22: Error response from daemon:
rpc error: code = InvalidArgument desc = only updates to Labels are allowed
Bumping to v23 makes Swarm create a new config object instead of mutating v22; the
orphaned v22 can be pruned after rollout.
autonomic-bot