patch 8.1.1563: crash when using closures

Problem:    Crash when using closures.
Solution:   Set reference in varlist of funccal when running the garbage
            collector. (Ozaki Kiichi, closes #4554, closes #4547)
diff --git a/src/version.c b/src/version.c
index f82f3c5..7c9a227 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1563,
+/**/
     1562,
 /**/
     1561,