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.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    454,
 /**/
     453,
 /**/