Change FT991 write_delay to 5ms -- was seeing many serial errors with 0ms

https://github.com/Hamlib/Hamlib/issues/1163

rigs/yaesu/ft991.c

@@ -141,7 +141,7 @@ const struct rig_caps ft991_caps =
     RIG_MODEL(RIG_MODEL_FT991),
     .model_name =         "FT-991",
     .mfg_name =           "Yaesu",
-    .version =            NEWCAT_VER ".14",
+    .version =            NEWCAT_VER ".15",
     .copyright =          "LGPL",
     .status =             RIG_STATUS_STABLE,
     .rig_type =           RIG_TYPE_TRANSCEIVER,

rigs/yaesu/ft991.h

@@ -165,7 +165,7 @@
 /* Delay between bytes sent to FT-991
  * Should not exceed value set in CAT TOT menu (rig default is 10 mSec)
  */
-#define FT991_WRITE_DELAY                    0
+#define FT991_WRITE_DELAY                    5
 
 
 /* Delay sequential fast writes */