patch 8.1.1385: signed/unsigned compiler warning

Problem:    Signed/unsigned compiler warning.
Solution:   Use STRLEN() instead of strlen().

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1385,
 /**/
     1384,
 /**/