patch 8.1.0178: warning for passing pointer to non-pointer argument

Problem:    Warning for passing pointer to non-pointer argument.
Solution:   Use zero instead of NULL.
diff --git a/src/version.c b/src/version.c
index 88d3b7e..1f94b01 100644
--- a/src/version.c
+++ b/src/version.c
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    178,
+/**/
     177,
 /**/
     176,