### Pull Request Checklist

<!-- Please read CONTRIBUTING.md before submitting your pull request -->

* [ ] Pull request is based on the develop branch
* [ ] Pull request includes a [changelog file](https://github.com/matrix-org/synapse/blob/master/CONTRIBUTING.md#changelog)
* [ ] Pull request includes a [sign off](https://github.com/matrix-org/synapse/blob/master/CONTRIBUTING.md#sign-off)
* [ ] Code style is correct (run the [linters](https://github.com/matrix-org/synapse/blob/master/CONTRIBUTING.md#code-style))