patch 8.1.0968: crash when using search pattern \%Ufffffc23

Problem:    Crash when using search pattern \%Ufffffc23.
Solution:   Limit character to INT_MAX. (closes #4009)
diff --git a/src/version.c b/src/version.c
index 825c5e5..13f54e3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    968,
+/**/
     967,
 /**/
     966,