patch 8.0.0166: JSON with a duplicate key gives an internal error

Problem:    JSON with a duplicate key gives an internal error. (Lcd)
Solution:   Give a normal error.  Avoid an error when parsing JSON from a
            remote client fails.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    166,
 /**/
     165,
 /**/