Bump robolectric from 4.8 to 4.8.1

Bumps [robolectric](https://github.com/robolectric/robolectric) from 4.8 to 4.8.1.
- [Release notes](https://github.com/robolectric/robolectric/releases)
- [Commits](https://github.com/robolectric/robolectric/compare/robolectric-4.8...robolectric-4.8.1

)

---
updated-dependencies:
- dependency-name: org.robolectric:robolectric
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>