patch 8.1.1157: Unicode tables are out of date

Problem:    Unicode tables are out of date.
Solution:   Update to Unicode 12. (Christian Brabandt, closes #4240)
diff --git a/src/version.c b/src/version.c
index 334a7ec..4daa41e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -772,6 +772,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1157,
+/**/
     1156,
 /**/
     1155,