Figure out how consumers can inherit our recommended rule configs #77

Currently, we instruct our consumers to copy/paste rule configs from our README which is not ideal. Ideally, our recommended ERBLint rule configs will automatically be pulled in as consumers bump dependencies of this gem. This is possible with Rubocop, and other linting libraries.

There is nothing in the Shopify/erb-lint README which hints that there's a way to inherit configurations from dependency gems.

However, upon digging into the codebase, I came across an inherit_gem.

Investigate whether there's actually a way to inherit dependency gem ERB Lint configurations and update the README accordingly.