Add `attributes.values` to Default cache_fragment_name

@benhutton What would you think about adding attributes.values to the default implementation of https://github.com/desiringgod/components-rails/blob/master/lib/components/rails/caching.rb#L26-L32`?

We're seeing a number of components where the #cache_key implementation is just attributes.values. Though there could be a case where a Component would not change based on an attribute provided and we wouldn't want the cache_fragment_name to change, that seems like an edge case and not a good reason to not implement this.

Also, if we do this, I think we could get away with not requiring #cache_key to be implemented. If #cache_key is implemented, it would effectively get added to this value.

Thoughts?

[benhutton]

@joeosburn-desiringgod I think I like the idea. I'm not so clear on your proposed implementation details...

Why would it be added to https://github.com/desiringgod/components-rails/blob/master/lib/components/rails/caching.rb#L26-L32%60? Why not just straight up make it the default value for #cache_key? Then you don't need to implement #cache_key, as you say.

Also, I tend think that implementing #cache_key should replace, not add to, attributes.values...

I can think of a case, for example, where calculating a key on everything in attributes.values might be more expensive than is necessary, and so I would specify a narrower key as a performance improvement. I can also think of a case where, like you say, you wouldn't want a certain value to change the cache key (though that seems a bit more far fetched, I agree.