Bump dill from 0.3.9 to 0.4.0

Bumps [dill](https://github.com/uqfoundation/dill) from 0.3.9 to 0.4.0.
- [Release notes](https://github.com/uqfoundation/dill/releases)
- [Commits](uqfoundation/dill@0.3.9...0.4.0)

---
updated-dependencies:
- dependency-name: dill
  dependency-version: 0.4.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]