patch 8.2.4101: warning for unused argument in tiny version

Problem:    Warning for unused argument in tiny version.
Solution:   Add "UNUSED".
diff --git a/src/version.c b/src/version.c
index d34f1a1..e6bcb1b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4101,
+/**/
     4100,
 /**/
     4099,