updated for version 7.4.281

Problem:    When a session file has more than one tabpage and 'showtabline' is
            one the positions may be slightly off.
Solution:   Set 'showtabline' to two while positioning windows.

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    281,
 /**/
     280,
 /**/