IAM instance role fix is unreleased

[cwjohnston]

Hello, and thank you for your work on this very useful project!

In working to replace an older internal fork of mkwheelhouse with an upstream release, I noticed that changes merged to master in #14, important to our use-case, have not been tagged nor released on Pypi.

I know it's been a while, but if at all possible, would you please tag and release a version of mkwheelhouse that contains the latest commits on master?