generateScopedName as a function

I’m trying to use generateScopedName as a function which should be possible, but it resolves as `undefined`. F.ex;

``generateScopedName: (localName, resourcePath) => { return 'foo' }``

And then if I do `console.log(typeof options.generateScopedName)` in `requireCssModule` it becomes undefined. Strings works fine as the tests shows, but not functions.

Start at the requireCssModule entry point mentioned in the report and trace how generateScopedName is read and passed through option handling. Review the existing tests for string generateScopedName behavior, then add coverage for the function form and confirm the function is preserved and used when the test suite passes.

Written by the indexing model from the issue text.