patch 8.1.1439: json_encode() is very slow for large results

Problem:    Json_encode() is very slow for large results.
Solution:   In the growarray use a growth of at least 50%. (Ken Takata,
            closes #4461)
diff --git a/src/version.c b/src/version.c
index 4b380d2..30c0831 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1439,
+/**/
     1438,
 /**/
     1437,