patch 8.0.0664: mouse does not work in tmux

Problem:    Mouse does not work in tmux. (lilydjwg)
Solution:   Add flag for SGR release being present.
diff --git a/src/version.c b/src/version.c
index 102e388..5be7d50 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    664,
+/**/
     663,
 /**/
     662,