patch 8.1.1308: the Normal highlight is not defined when compiled with GUI

Problem:    The Normal highlight is not defined when compiled with GUI.
Solution:   Always define Normal. (Christian Brabandt, closes #4072)
diff --git a/src/version.c b/src/version.c
index ea04ff9..63cfd8d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1308,
+/**/
     1307,
 /**/
     1306,