patch 8.0.1723: using one item array size declaration is misleading

Problem:    Using one item array size declaration is misleading.
Solution:   Instead of using "[1]" and actually using a larger array, use
            "[]".  This is to verify that this C99 feature works for all
            compilers.
diff --git a/src/version.c b/src/version.c
index 9989f9f..bdd1a3d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1723,
+/**/
     1722,
 /**/
     1721,