Bump guava from 20.0 to 23.0
Bump guava from 20.0 to 23.0

Bumps [guava](https://github.com/google/guava) from 20.0 to 23.0.
- [Release notes](https://github.com/google/guava/releases)
- [Commits](https://github.com/google/guava/compare/v20.0...v23.0)

---
updated-dependencies:
- dependency-name: com.google.guava:guava
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
lukas-krecan/future-converter