patch 8.2.1712: Vim9: leaking memory when calling a lambda

Problem:    Vim9: leaking memory when calling a lambda.
Solution:   Decrement function reference from ISN_DCALL.
diff --git a/src/version.c b/src/version.c
index aa09b70..615abc7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1712,
+/**/
     1711,
 /**/
     1710,