patch 8.1.0001: the netrw plugin does not work

Problem:    The netrw plugin does not work.
Solution:   Make it accept version 8.x.

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1,
 /**/
     0
 };