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.
def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        if isinstance(o, datetime):
            return str(o)
        if isinstance(o, six.binary_type):
            return to_str(o)
        return super(CustomEncoder, self).default(o)
class FuncThread (threading.Thread):
    def __init__(self, func, params, quiet=False):
        threading.Thread.__init__(self)
        self.daemon = True
        self.params = params
        self.func = func
        self.quiet = quiet
    def run(self):
        try:
            self.func(self.params)
        except Exception:
            if not self.quiet:
                LOGGER.warning('Thread run method %s(%s) failed: %s' %
                    (self.func, self.params, traceback.format_exc()))
    def stop(self, quiet=False):
        if not quiet and not self.quiet:
            LOGGER.warning('Not implemented: FuncThread.stop(..)')
class ShellCommandThread (FuncThread):