patch 8.2.2021: Vim9: get E1099 when autocommand resets did_emsg

Problem:    Vim9: get E1099 when autocommand resets did_emsg.
Solution:   Add did_emsg_cumul. (closes #7336)
diff --git a/src/version.c b/src/version.c
index 4fdc0f1..aeadf36 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2021,
+/**/
     2020,
 /**/
     2019,