Add regions to the auto-complete

[rsack]

Would like to suggest adding the actual regions to the --region auto-complete (e.g. show us-east... and so on).

It would also be great to support the --region (and other options) in other places except after the service (e.g. also at the end).

[jamesls]

Good idea, marking as feature request.

[imWillX]

+1

[jamesls]

This should now be possible with the latest botocore package, which now exposes an api to get available regions (https://github.com/boto/botocore/blob/develop/botocore/session.py#L829)