add support for .ghooksrc since touching package.json is a little bit too opinionated.

[kilianc]

package.json get's published to npm and other registries, other than being a really intimate place for most projects. There should be an option to read .ghooksrc first.

For example I don't even have a config section in my package.json.

[kilianc]

this would become obsolete if #34 lands.

[kentcdodds]

As noted in #34, we're not going to do this. The config section is the official place to put stuff like this. Thanks!