Allow to configure commintlint in package.json or with json/yaml file

[pvdlg]

It would be convenient to allow commitlint to be configured within package.json or with a json or yaml file, similarly to eslint, prettier, stylelint etc...

cosmiconfig allow to do that pretty easily (as a replacement of rc).

Would you be open to such PR ?

[calebeby]

Haha I was just about to open this same issue

[marionebl]

Sure, some help with this would be awesome.