patch 8.1.0113: compiler warning for unused variable

Problem:    Compiler warning for unused variable. (Yegappan Lakshmanan)
Solution:   Add UNUSED. (Christian Brabandt)
diff --git a/src/version.c b/src/version.c
index 06ed8ce..433881c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    113,
+/**/
     112,
 /**/
     111,