rust: set MSRV to 1.57

Due to dependencies, this bumps MSRV to 1.57. These dependencies could
be kept back to some degree but I am unsure whether this would bring value.
At this point, more and more libraries require version 2021, which was introduced
with rust 1.56.1.

Also in this commit, Cargo.toml declares the aws sdk dev dependencies as normal
dependencies to not require them at all, unless building with the KMS
feature.

Signed-off-by: Petre Eftime <epetre@amazon.com>

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                rust: [1.46.0, stable, nightly]
+                rust: [1.57.0, stable, nightly]
                 key_feature_set:
                   - key_openssl_pkey
         steps:

Cargo.toml

@@ -8,6 +8,7 @@ keywords = ["COSE"]
 categories = ["cryptography"]
 repository = "https://github.com/awslabs/aws-nitro-enclaves-cose"
 description = "This library aims to provide a safe Rust implementation of COSE, with COSE Sign1 currently implemented."
+rust-version = "1.57"
 
 [dependencies]
 serde_cbor = { version="0.11", features = ["tags"] }
@@ -17,20 +18,19 @@ serde_with = { version = "1.5", default_features = false }
 openssl = { version = "0.10", optional = true }
 tss-esapi = { version = "6.1", optional = true }
 aws-sdk-kms = { version = "0.16", optional = true }
-tokio = { version = "1.20", features = ["rt"], optional = true }
+tokio = { version = "1.20", features = ["rt", "macros"], optional = true }
+aws-config = { version = "0.46", optional = true }
 
 [dependencies.serde]
 version = "1.0"
 features = ["derive"]
 
 [dev-dependencies]
 hex = "0.4"
-tokio = { version = "1.20", features = ["macros"] }
-aws-config = "0.46"
 
 [features]
 default = ["key_openssl_pkey"]
 key_openssl_pkey = ["openssl"]
 key_tpm = ["tss-esapi", "openssl"]
-key_kms = ["aws-sdk-kms", "tokio", "key_openssl_pkey"]
+key_kms = ["aws-sdk-kms", "aws-config", "tokio", "key_openssl_pkey"]
 

README.md

@@ -1,11 +1,12 @@
-[![status]][actions] [![version]][crates.io] [![docs]][docs.rs]
+[![status]][actions] [![version]][crates.io] [![docs]][docs.rs] ![msrv]
 
 [status]: https://img.shields.io/github/workflow/status/awslabs/aws-nitro-enclaves-cose/CI/master
 [actions]: https://github.com/awslabs/aws-nitro-enclaves-cose/actions?query=branch%3Amain
 [version]: https://img.shields.io/crates/v/aws-nitro-enclaves-cose.svg
 [crates.io]: https://crates.io/crates/aws-nitro-enclaves-cose
 [docs]: https://img.shields.io/docsrs/aws-nitro-enclaves-cose
 [docs.rs]: https://docs.rs/aws-nitro-enclaves-cose
+[msrv]: https://img.shields.io/badge/MSRV-1.57-blue
 
 ## COSE for AWS Nitro Enclaves