patch 8.0.0820: GUI: cursor in terminal window lags behind

Problem:    GUI: cursor in terminal window lags behind.
Solution:   call gui_update_cursor() under different conditions. (Ozaki
            Kiichi, closes #1893)
diff --git a/src/version.c b/src/version.c
index 2d4c50e..8733db2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    820,
+/**/
     819,
 /**/
     818,