Change dummy ptt_type to None

https://github.com/Hamlib/Hamlib/issues/888

rigs/dummy/dummy.c

@@ -2244,12 +2244,12 @@ struct rig_caps dummy_caps =
     RIG_MODEL(RIG_MODEL_DUMMY),
     .model_name =     "Dummy",
     .mfg_name =       "Hamlib",
-    .version =        "20211130.0",
+    .version =        "20211213.0",
     .copyright =      "LGPL",
     .status =         RIG_STATUS_STABLE,
     .rig_type =       RIG_TYPE_OTHER,
     .targetable_vfo = RIG_TARGETABLE_PTT | RIG_TARGETABLE_RITXIT | RIG_TARGETABLE_FREQ | RIG_TARGETABLE_MODE | RIG_TARGETABLE_SPECTRUM,
-    .ptt_type =       RIG_PTT_RIG,
+    .ptt_type =       RIG_PTT_NONE,
     .dcd_type =       RIG_DCD_RIG,
     .port_type =      RIG_PORT_NONE,
     .has_get_func =   DUMMY_FUNC,