Update aws-config requirement from 0.55 to 0.56

Updates the requirements on [aws-config](https://github.com/awslabs/smithy-rs) to permit the latest version.
- [Release notes](https://github.com/awslabs/smithy-rs/releases)
- [Changelog](https://github.com/awslabs/smithy-rs/blob/main/CHANGELOG.md)
- [Commits](https://github.com/awslabs/smithy-rs/commits)

---
updated-dependencies:
- dependency-name: aws-config
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

ethcontract/Cargo.toml

@@ -32,7 +32,7 @@ ws-tls-tokio = ["web3/ws-tls-tokio"]
 ws-tokio = ["web3/ws-tokio"]
 
 [dependencies]
-aws-config = { version = "0.55", optional = true }
+aws-config = { version = "0.56", optional = true }
 aws-sdk-kms = { version = "0.28", optional = true }
 arrayvec = "0.7"
 ethcontract-common = { version = "0.25.1", path = "../ethcontract-common" }