patch 8.0.0318: small mistake in 7x13 font name

Problem:    Small mistake in 7x13 font name.
Solution:   Use ISO 8859-1 name instead of 10646-1. (Kazunobu Kuriyama)
diff --git a/src/version.c b/src/version.c
index 50c6fb1..1448e98 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    318,
+/**/
     317,
 /**/
     316,