deps: bump stun from 0.5.0 to 0.5.1

Bumps [stun](https://github.com/webrtc-rs/stun) from 0.5.0 to 0.5.1.
- [Release notes](https://github.com/webrtc-rs/stun/releases)
- [Commits](https://github.com/webrtc-rs/stun/commits)

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

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

Author: dependabot[bot]