Is there an existing issue for this?

• I have searched existing issues, it hasn't been reported yet

Use case description

It would be very helpful in tracking Serverless Framework requests if it used a user-agent header of "serverless-framework" or the like.

I believe this would be configured in packages/serverless/lib/aws/v3/client-factory.js by passing in a custom user-agent configuration.

Proposed solution (optional)

For example, something like this:

user-agent: aws-sdk-js/3.958.0 ua/2.1 os/linux lang/js md/nodejs#20.19.6 serverless-framework/4.30.0