patch 8.0.0568: 1gd may hang

Problem:    "1gd" may hang.
Solution:   Don't get stuck in one position. (Christian Brabandt, closes #1643)
diff --git a/src/version.c b/src/version.c
index 487712d..b9790d4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    568,
+/**/
     567,
 /**/
     566,