### Update dependencies

Automatically created PR from the [`dependabot_updates`](https://github.com/Materials-Consortia/optimade-python-tools/tree/dependabot_updates) branch.

For more information see the ["Dependabot updates" workflow](https://github.com/Materials-Consortia/optimade-python-tools/blob/master/.github/workflows/ci_dependabot.yml).

#### To-do

- [ ] Check that the diff is sensible, and that tests and builds pass with the new dependency versions.
- [ ] Check whether the dependency versions in [`setup.py`](https://github.com/Materials-Consortia/optimade-python-tools/blob/ci/update-dependencies/setup.py) need updating, keeping the version requirements as loose as possible.
- [ ] Make sure that the PR is **squash** merged, with a sensible commit message.
