patch 8.0.0454: compiler warnings for "always true" comparison

Problem:    Compiler warnings for comparing unsigned char with 256 always
            being true. (Manuel Ortega)
Solution:   Add type cast.
diff --git a/src/version.c b/src/version.c
index 28c9294..2f9c315 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    454,
+/**/
     453,
 /**/
     452,