update msrv to 1.56 (#2777)

* update msrv to 1.56

* remove transitive dashmap dependency

closes #2747

actix-web-codegen/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased - 2021-xx-xx
 - Fix support for guard paths in route handler macros. [#2771]
+- Minimum supported Rust version (MSRV) is now 1.56 due to transitive `hashbrown` dependency.
 
 [#2771] https://github.com/actix/actix-web/pull/2771
 

actix-web-codegen/README.md

@@ -4,7 +4,7 @@
 
 [![crates.io](https://img.shields.io/crates/v/actix-web-codegen?label=latest)](https://crates.io/crates/actix-web-codegen)
 [![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=4.0.0)](https://docs.rs/actix-web-codegen/4.0.0)
-[![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
+![Version](https://img.shields.io/badge/rustc-1.56+-ab6000.svg)
 ![License](https://img.shields.io/crates/l/actix-web-codegen.svg)
 <br />
 [![dependency status](https://deps.rs/crate/actix-web-codegen/4.0.0/status.svg)](https://deps.rs/crate/actix-web-codegen/4.0.0)

actix-web-codegen/tests/trybuild.rs

@@ -1,4 +1,4 @@
-#[rustversion::stable(1.54)] // MSRV
+#[rustversion::stable(1.56)] // MSRV
 #[test]
 fn compile_macros() {
     let t = trybuild::TestCases::new();