build(deps): bump libp2p from 5464092 to b4c7dfc (#124)

Bumps [libp2p](https://github.com/libp2p/rust-libp2p) from `5464092` to `b4c7dfc`.
- [Release notes](https://github.com/libp2p/rust-libp2p/releases)
- [Commits](libp2p/rust-libp2p@5464092...b4c7dfc)

---
updated-dependencies:
- dependency-name: libp2p
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>