Merge branch 'ps/maintenance-detach-fix'

Maintenance tasks other than "gc" now properly go background when "git maintenance" runs them. * ps/maintenance-detach-fix: run-command: fix detaching when running auto maintenance builtin/maintenance: add a `--detach` flag builtin/gc: add a `--detach` flag builtin/gc: stop processing log file on signal builtin/gc: fix leaking config values builtin/gc: refactor to read config into structure config: fix constness of out parameter for `git_config_get_expiry()`