i don't need injection but Store already has a [convert](https://github.com/twitter/storehaus/blob/develop/storehaus-core/src/main/scala/com/twitter/storehaus/EnrichedStore.scala#L37) function defined and I thought it would be a good idea to be consistent with that function. In most client client would be able able to use injections defined for Store.convert and Sink.convert