Chore: Fix probe_tcp_connect, by adding a low timeout

Author: amotl

pytest_mqtt/util.py

@@ -15,6 +15,7 @@ def probe_tcp_connect(host: str, port: int) -> bool:
     https://github.com/lovelysystems/lovely.testlayers/blob/0.7.0/src/lovely/testlayers/util.py#L6-L13
     """
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    s.settimeout(0.1)
     ex = s.connect_ex((host, port))
     if ex == 0:
         s.close()