patch 8.1.2038: has('vimscript-4') is always 0

Problem:    has('vimscript-4') is always 0.
Solution:   Add "vimscript-4" to the feature table. (Naruhiko Nishino,
            closes #4941)

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2038,
 /**/
     2037,
 /**/