patch 7.4.2021
Problem:    Still too many buf_valid() calls.
Solution:   Make au_new_curbuf a bufref.  Use bufref_valid() in more places.
diff --git a/src/version.c b/src/version.c
index ebaef41..04b7c01 100644
--- a/src/version.c
+++ b/src/version.c
@@ -759,6 +759,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2021,
+/**/
     2020,
 /**/
     2019,