Add missing -B arg

rcon/gui.py

@@ -37,6 +37,10 @@ def get_args() -> Namespace:
     """Parses the command line arguments."""
 
     parser = ArgumentParser(description='A minimalistic, GTK-based RCON GUI.')
+    parser.add_argument(
+        '-B', '--battleye', action='store_true',
+        help='use BattlEye RCon instead of Source RCON'
+    )
     parser.add_argument(
         '-d', '--debug', action='store_true',
         help='print additional debug information'