THRIFT-5600: rust lib to upgrade to edition 2021
Client: rs
Patch: Jiayu Liu

This closes #2628
diff --git a/lib/rs/test/Cargo.toml b/lib/rs/test/Cargo.toml
index 47b8cbf..a1c6836 100644
--- a/lib/rs/test/Cargo.toml
+++ b/lib/rs/test/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "kitchen-sink"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 license = "Apache-2.0"
 authors = ["Apache Thrift Developers <dev@thrift.apache.org>"]
 publish = false