remove unneeded use of FindBin
use Class::Load directly, rather than Class::MOP's wrapper
RT#86041: fix coercion result on failure

attempt to load class in the validation itself, not the coercion, so we can
fail out properly, without returning an undef result when attempting to coerce
a bad string.
It's MUCH easier to simply test with the Moose::Meta::TypeConstraint API,
rather than attempting to shoehorn into a Moose class.
use ISO8601 date format in changelog
bump version, repo info for release
oops, shouldnt advise using coerce - that does nothing now
might as well add self to the list now