Must specify userName when calling with non-User credentials #17
Description
On some resources I have this error on update / delete.
I'm sure that it happens for policies - maybe some others but I have no example right now.
It seems to come from https://github.com/winebarrel/miam/blob/v0.2.4/lib/miam/driver.rb#L410 (for updates) where it tries to construct the ARN for the policy.
The ARN is constructed here https://github.com/winebarrel/miam/blob/v0.2.4/lib/miam/driver.rb#L463 with the user name.
(However, the ARN for a policy has no user name in it - but the account ID)
When it tries to fetch the current user, it fails - and then cannot construct the request.
However I'm pretty sure the resulting ARN won't identify the policy as it needs the account ID.