rbacLogin token argument is optional

As spotted by @tlevens

pyjapc/_japc.py

@@ -394,7 +394,7 @@ class PyJapc:
         loginDialog: bool = False,
         readEnv: bool = True,
         *,
-        token: typing.Union[bytes, pyjapc_types.PyRbacTokenLike, None],
+        token: typing.Union[bytes, pyjapc_types.PyRbacTokenLike, None] = None,
     ) -> None:
         """Perform RBAC authentication.