Handle connection refuse error

[RadxaYuntian]

Got the program crashed with checking a closed port:

Traceback (most recent call last):
  File "/usr/bin/tcping", line 33, in <module>
    sys.exit(load_entry_point('tcping==0.1.1rc1', 'console_scripts', 'tcping')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/tcping.py", line 205, in cli
    ping.ping(count)
  File "/usr/bin/tcping.py", line 169, in ping
    cost_time = self.timer.cost(
                ^^^^^^^^^^^^^^^^
  File "/usr/bin/tcping.py", line 108, in cost
    func(*arg)
  File "/usr/bin/tcping.py", line 45, in connect
    self._s.connect((host, int(port)))
ConnectionRefusedError: [Errno 111] Connection refused