v0.6.3

Updated module dependencies and fixed package test (#9)

As a part of gobuffalo/buffalo#2152, updated dependencies.

Just included two orthogonal changes in a single PR since they are not a great deal.

* Updated dependencies to a recent version of modules. mainly for testify.
* Fixed test case for Package(). go 1.16 changed its behavior when running go list ... and does not automatically add the given package anymore.