patch 8.2.0680: PTYGROUP and PTYMODE are unused

Problem:    PTYGROUP and PTYMODE are unused.
Solution:   Remove from autoconf. (closes #6024)
diff --git a/src/version.c b/src/version.c
index eb88916..02f7b6e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    680,
+/**/
     679,
 /**/
     678,