patch 8.2.1298: compiler warning for unused argument in small version

Problem:    Compiler warning for unused argument in small version.
Solution:   Add UNUSED.
diff --git a/src/version.c b/src/version.c
index c45c155..58a434a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1298,
+/**/
     1297,
 /**/
     1296,