patch 8.2.1952: Vim9: crash when using a NULL dict key

Problem:    Vim9: crash when using a NULL dict key.
Solution:   Use a NULL dict key like an empty string. (closes #7249)
diff --git a/src/version.c b/src/version.c
index d677744..98a3ab1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1952,
+/**/
     1951,
 /**/
     1950,