patch 8.2.1590: Vim9: bufnr() doesn't take "true" argument

Problem:    Vim9: bufnr() doesn't take "true" argument.
Solution:   use tv_get_bool_chk(). (closes #6863)
diff --git a/src/version.c b/src/version.c
index 26a30c1..53a3ed0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1590,
+/**/
     1589,
 /**/
     1588,