Transformer-embeddings

Breaking
* Dropping py37 support ([`9c6c81e`](https://github.com/HeadspaceMeditation/transformer-embeddings/commit/9c6c81e5258ec4a72d97da60223ddd1694ea02fe))

Documentation
* Updating docs to communicate breaking python support changes ([18](https://github.com/HeadspaceMeditation/transformer-embeddings/issues/18)) ([`9c6c81e`](https://github.com/HeadspaceMeditation/transformer-embeddings/commit/9c6c81e5258ec4a72d97da60223ddd1694ea02fe))

Feature
* Separate S3 dependencies to an optional ([16](https://github.com/HeadspaceMeditation/transformer-embeddings/issues/16)) ([`036cdc8`](https://github.com/HeadspaceMeditation/transformer-embeddings/commit/036cdc887ed091460921ed3edb314b71455df221))