chore(deps): update dash-mpd requirement from ^0.12.0 to ^0.13.0

Updates the requirements on [dash-mpd](https://github.com/emarsden/dash-mpd-rs) to permit the latest version.
- [Changelog](https://github.com/emarsden/dash-mpd-rs/blob/main/CHANGELOG.md)
- [Commits](emarsden/dash-mpd-rs@v0.12.0...v0.13.0)

---
updated-dependencies:
- dependency-name: dash-mpd
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

crates/plex-api/Cargo.toml

@@ -44,7 +44,7 @@ async-std = { version = "^1.12", features = ["attributes"] }
 plex-api-test-helper = { path = "../plex-api-test-helper" }
 rstest = "^0.18.1"
 rpassword = "^7.2"
-dash-mpd = "^0.12.0"
+dash-mpd = "^0.13.0"
 hls_m3u8 = "^0.4.1"
 mp4 = "^0.13.0"
 mp3-metadata = "^0.3.4"