Bug Fixes
* **when:** ensure `then_enter_with` accepts `None` ([137](https://github.com/mcous/decoy/issues/137)) ([864aad7](https://github.com/mcous/decoy/commit/864aad7)), closes [#135](https://github.com/mcous/decoy/issues/135)
Features
* **when:** allow `then_do` to take an async function ([4ae00e5](https://github.com/mcous/decoy/commit/4ae00e5)), closes [#136](https://github.com/mcous/decoy/issues/136)