patch 9.0.0204: indexof() may leak memory

Problem:    indexof() may leak memory.
Solution:   Free allocated values. (Yegappan Lakshmanan, closes #10916)
diff --git a/src/version.c b/src/version.c
index f901eea..3b5193f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    204,
+/**/
     203,
 /**/
     202,