patch 9.1.0620: Vim9: segfauls with null objects

Problem:  Vim9: segfauls with null objects
          (after v9.1.0219)
Solution: Check object pointer being NULL
          (Ernie Rael)

fixes: #15338
closes: #15349

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 298d577..806e3c5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    620,
+/**/
     619,
 /**/
     618,