patch 8.2.1866: Vim9: appending to pushed blob gives wrong result

Problem:    Vim9: appending to pushed blob gives wrong result.
Solution:   Set ga_maxlen when copying a blob.
diff --git a/src/version.c b/src/version.c
index 2894ded..1b60ebd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1866,
+/**/
     1865,
 /**/
     1864,