Reduce keepalive_interval from 60 to 10 seconds for ServerReconnecter

it was increased in a50f36b
from 3 to 60, but since then faf-uid calculator was improved
and reconnection process takes much less time
60 secs now look a bit harsh, so let's relax th interval to 10 seconds

src/client/connection.py

@@ -47,7 +47,7 @@ def __init__(self, connection: ServerConnection) -> None:
         self._keepalive = False
         self._keepalive_timer = QtCore.QTimer(self)
         self._keepalive_timer.timeout.connect(self._ping_connection)
-        self.keepalive_interval = 60 * 1000
+        self.keepalive_interval = 10 * 1000
         self._waiting_for_message = False
 
     @property