Bump tower-service from 0.3.0 to 0.3.1 (#765)
Bump tower-service from 0.3.0 to 0.3.1 (#765)

Bumps [tower-service](https://github.com/tower-rs/tower) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/tower-rs/tower/releases)
- [Commits](https://github.com/tower-rs/tower/compare/tower-0.3.0...tower-0.3.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
alex/otp-cop