Permit use of service role with change set workflow

[nullus]

Add --service-role-arn option to "change-set create"

[trembylene]

Hi Nullus!

This functionality is a good addition, thank you for your PR.

Before I can merge this however, the PR needs two more things.
Can you please update the documentation to reflect the addition of the new functionality, and write a test to cover this use case?

Thank you,
Jess

[nullus]

Can you please update the documentation to reflect the addition of the new functionality

Absolutely, do you want that in the README.md? Any preference on whether it's mentioned under the existing usage of --service-role-arn or added under "Change-set support"?

... write a test to cover this use case?

I couldn't see any equivalent tests for that parameter for the existing use case, so I didn't add one for this. Where should that be added?

[mukaibot]

Can you please update the documentation to reflect the addition of the new functionality

Absolutely, do you want that in the README.md? Any preference on whether it's mentioned under the existing usage of --service-role-arn or added under "Change-set support"?

Change-set support sounds good! I think most people will look for it there. Thanks!

... write a test to cover this use case?

I couldn't see any equivalent tests for that parameter for the existing use case, so I didn't add one for this. Where should that be added?

Yeah, we don't have tests for change-sets! @trembylene and I are new to the project so we're still catching up on some things. Would you feel comfortable creating a change_set_spec.rb file that tests only your needed parameter? Something simple is fine, we don't expect you to write tests for the whole change set feature. I guess that's on us!

[lukeck]

Thanks for adding tests @amcinnes! Looks good.