Update stun requirement from 0.6.0 to 0.7.0

Updates the requirements on [stun](https://github.com/webrtc-rs/webrtc) to permit the latest version.
- [Release notes](https://github.com/webrtc-rs/webrtc/releases)
- [Commits](webrtc-rs/webrtc@v0.6.0...dtls-v0.7.0)

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

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

Cargo.toml

@@ -30,7 +30,7 @@ reqwest = { version = "0.12.8", features = [
 serde = { version = "1", features = ["serde_derive"] }
 serde_json = "1"
 smallvec = { version = "1.13.2", features = ["serde"] }
-stun = "0.6.0"
+stun = "0.7.0"
 tokio = { version = "1.41.0", features = [
   "rt",
   "rt-multi-thread",