patch 8.2.1560: using NULL pointers in some code

Problem:    Using NULL pointers in some code. (James McCoy)
Solution:   Avoid adding to a NULL pointer.  Use byte as unsigned.
diff --git a/src/version.c b/src/version.c
index 158f2a3..29f4363 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1560,
+/**/
     1559,
 /**/
     1558,