Should not lookup .browserslistrc by default

[hulkish]

Can we allow for this behavior: https://github.com/Nyalab/caniuse-api/blob/master/src/index.js#L68 to somehow be overridable, so that it does not seek a browserslist config, by default?

Otherwise, I'm worried this can lead to side effects where you prefer your own browserslist config. It's also wasteful to perform sync io fs operations at module level, like this.