patch 9.0.0285: it is not easy to change the command line from a plugin

Problem:    It is not easy to change the command line from a plugin.
Solution:   Add setcmdline(). (Shougo Matsushita, closes #10869)
diff --git a/src/version.c b/src/version.c
index 2e48687..6b4bdfa 100644
--- a/src/version.c
+++ b/src/version.c
@@ -708,6 +708,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    285,
+/**/
     284,
 /**/
     283,