Merge pull request #53 from http-rs/edition-2021

edition 2021

Author: jbr

Cargo.toml

@@ -6,7 +6,7 @@ repository = "https://github.com/http-rs/async-session"
 documentation = "https://docs.rs/async-session"
 description = "Async session support with pluggable middleware"
 readme = "README.md"
-edition = "2018"
+edition = "2021"
 keywords = []
 categories = []
 authors = [