Bump discv5 from 0.2.2 to 0.3.1

Bumps [discv5](https://github.com/sigp/discv5) from 0.2.2 to 0.3.1.
- [Release notes](https://github.com/sigp/discv5/releases)
- [Commits](sigp/discv5@v0.2.2...v0.3.1)

---
updated-dependencies:
- dependency-name: discv5
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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