Providing instructions on how to generate Swift client code

[jguz1988]

Describe the issue

I'd like to generate Swift client code from Smithy models I already created. Would it be possible to provide step-by-step instructions on how to do this? For instance, in the README.md file like you did for the smithy-typescript repository.

Links

https://github.com/awslabs/smithy-swift/blob/main/README.md

[ganeshnj]

Related to awslabs/aws-sdk-swift#186