increase minimum versions of Moo and Throwable::Error dependenices

This commit fixes the test failures that occurred here:

http://www.cpantesters.org/cpan/report/4c87f201-6d9f-1014-8d2f-b3391ede6b02

Specifically:

- Throwable::Error 0.200003 starts using Moo
- Moo 1.000004 allows 'has \@attributes'

~~You might wish to pull up the Moo req up to 1.000007 even, as the intervening releases are all bug fixes.~~