patch 8.1.0686: when 'y' is in 'cpoptions' yanking for the clipboard changes redo

Problem:    When 'y' is in 'cpoptions' yanking for the clipboard changes redo.
Solution:   Do not use the 'y' flag when "gui_yank" is TRUE. (Andy Massimino,
            closes #3760)
diff --git a/src/version.c b/src/version.c
index b9fe301..62edc78 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    686,
+/**/
     685,
 /**/
     684,