`findAll` and `findOne` no longer part of the `Adapter` interface

[LanceStasinski]

We are using a custom adapter that has custom implementations of findAll and findOne. We are trying to update to css-select v6, but it looks like findAll and findOne are no longer part of the Adapter interface. The release logs don't mention an update to the api. Is the removal of findAll and findOne a purposeful change? If so, the link in the Custom adapters section of the README should probably be updated.