Support asynchronous responseInterceptor

[rg1]

Description

Analogous to Issue #1249, I would need the responseInterceptor to be able to modify the response asynchronously.

Motivation and Context

The idea is for the responseInterceptor to make another request and use the result in place of the previously received one. In particular I need this, because I need to handle redirect requests myself, because I need to receive cookies set on the redirect response.

How Has This Been Tested?

I've added a test to the test suite that performs a new request from the responseInterceptor (although from an error response, not a redirect).

Types of changes

• No code changes (changes to documentation, CI, metadata, etc)
• Dependency changes (any modification to dependencies in package.json)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[shockey]

I'd rather this PR use async/await syntax, since we have support for it 😄

[rg1]

I've updated the code to use async/await as requested. Sorry that I didn't realize it was supported.

I guess fixing #1249 is now simply a matter of adding another await (and a test). I could add that as well if you like, or submit another pull request once this is merged.

[shockey]

@rg1 please do! might as well knock both out at once 😄

[rg1]

@shockey I've pushed the change Monday. Is anything else needed?