Why has coverage been locked to `==4.0.3` for two years? Why not `>=4.0.0`?

If I add localstack to my pipenv, I can't lock because of this unnecessary dependency.
last_clean_time=last_cache_clean_time, max_age=CACHE_MAX_AGE):
    mutex_clean.acquire()
    time_now = now()
    try:
        if last_clean_time['time'] > time_now - CACHE_CLEAN_TIMEOUT:
            return
        for cache_file in set(glob.glob(file_pattern)):
            mod_time = os.path.getmtime(cache_file)
            if time_now > mod_time + max_age:
                rm_rf(cache_file)
        last_clean_time['time'] = time_now
    finally:
        mutex_clean.release()
    return time_now
def truncate(data, max_length=100):
    return (data[:max_length] + '...') if len(data) > max_length else data
def parallelize(func, list, size=None):
    if not size:
        size = len(list)
    if size <= 0:
        return None
    pool = Pool(size)
    result = pool.map(func, list)
    pool.close()
    pool.join()
    return result