patch 8.0.0304: assign test fails in the GUI

Problem:    Assign test fails in the GUI.
Solution:   Skip the test for setting t_k1.
diff --git a/src/testdir/test_assign.vim b/src/testdir/test_assign.vim
index 22aa4a1..4a4c644 100644
--- a/src/testdir/test_assign.vim
+++ b/src/testdir/test_assign.vim
@@ -15,11 +15,13 @@
   call assert_match('t_te.*^[[yes;', execute("set termcap"))
   let &t_te = old_t_te
 
-  " Key code
-  let old_t_k1 = &t_k1
-  let &t_k1 = "that"
-  call assert_match('t_k1.*that', execute("set termcap"))
-  let &t_k1 = old_t_k1
+  if !has('gui_running')
+    " Key code
+    let old_t_k1 = &t_k1
+    let &t_k1 = "that"
+    call assert_match('t_k1.*that', execute("set termcap"))
+    let &t_k1 = old_t_k1
+  endif
 
   call assert_fails('let x = &t_xx', 'E15')
   let &t_xx = "yes"
diff --git a/src/version.c b/src/version.c
index 037c2dd..9273b2b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    304,
+/**/
     303,
 /**/
     302,