Upgrade rust/crates/structopt to 0.3.18

Test: make
Change-Id: Ib5d515b0f5e9ac7fdd0f2f8e2f00ecf54dbf63ca
diff --git a/tests/macro-errors.rs b/tests/macro-errors.rs
index ae4f5a2..54b405a 100644
--- a/tests/macro-errors.rs
+++ b/tests/macro-errors.rs
@@ -5,7 +5,7 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 
-#[rustversion::attr(any(not(stable), before(1.39)), ignore)]
+#[rustversion::attr(any(not(stable), before(1.43)), ignore)]
 #[test]
 fn ui() {
     let t = trybuild::TestCases::new();