patch 8.2.4280: list-dict test crashes

Problem:    list-dict test crashes.
Solution:   Check declared type for add().
diff --git a/src/version.c b/src/version.c
index 6d89615..978e869 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4280,
+/**/
     4279,
 /**/
     4278,