patch 8.2.4084: memory leak when looking for autoload prefixed variable

Problem:    Memory leak when looking for autoload prefixed variable.
Solution:   Free the concatenated string.
diff --git a/src/version.c b/src/version.c
index ecfa17d..957ccee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4084,
+/**/
     4083,
 /**/
     4082,