Add support for account ID to AWS credentials

[jbelkins]

Describe the feature

Account ID-based endpoints requires the resolution and passing of AWS account ID along with AWS credentials. The current aws-crt-swift implementation of AWS credentials does not have a field for account ID.

Account ID should be resolved when it is available along with AWS credentials. AWS credential resolution should never fail due to failure to resolve AWS account ID. Separate tickets will be filed to add AWS account ID resolution to certain other AWS credential resolvers.

To allow for testing of downstream work, please add support for the account ID field to the static credential resolver.

Use Case

To allow for the implementation of account ID-based endpoints in the AWS SDK for Swift.

Proposed Solution

Add account ID as an optional string-typed field on the underlying C implementation of AWS credentials, and add account ID support to Swift bindings (initializers, accessors, etc) to allow for use of the field.

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change