Fix TS-2000 set_ptt

https://github.com/Hamlib/Hamlib/issues/1321

rigs/kenwood/kenwood.c

@@ -4861,7 +4861,7 @@ int kenwood_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
         case RIG_PTT_ON:
         case RIG_PTT_ON_MIC:
         case RIG_PTT_ON_DATA:
-            ptt_cmd = (vfo == RIG_VFO_C) ? "TX1" : "TX0";
+            ptt_cmd = "TX";
             break;
 
         case RIG_PTT_OFF:

rigs/kenwood/kenwood.h

@@ -28,7 +28,7 @@
 #include "token.h"
 #include "idx_builtin.h"
 
-#define BACKEND_VER "20230517"
+#define BACKEND_VER "20230626"
 
 #define EOM_KEN ';'
 #define EOM_TH '\r'