patch 8.1.2134: modifier keys are not always recognized

Problem:    Modifier keys are not always recognized.
Solution:   Handle key codes generated by xterm with modifyOtherKeys set.
            Add this to libvterm so we can debug it.

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2134,
 /**/
     2133,
 /**/