patch 8.2.1867: Vim9: argument to add() not checked for blob

Problem:    Vim9: argument to add() not checked for blob.
Solution:   Add the BLOBAPPEND instruction.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1867,
 /**/
     1866,
 /**/