patch 8.0.0169: json_decode() may run out of stack space

Problem:    For complicated string json_decode() may run out of stack space.
Solution:   Change the recursive solution into an iterative solution.
diff --git a/src/version.c b/src/version.c
index 6294188..23dd5ae 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    169,
+/**/
     168,
 /**/
     167,