patch 8.1.2135: with modifyOtherKeys Alt-a does not work properly

Problem:    With modifyOtherKeys Alt-a does not work properly.
Solution:   Remove the ALT modifier.  Get multi-byte after applying ALT.
diff --git a/src/version.c b/src/version.c
index 7289c9b..f22db55 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2135,
+/**/
     2134,
 /**/
     2133,