Bump mopidy-iris from 3.54.2 to 3.68.0 (#2060)

Bumps [mopidy-iris](https://github.com/jaedb/iris) from 3.54.2 to 3.68.0.
- [Release notes](https://github.com/jaedb/iris/releases)
- [Commits](jaedb/Iris@3.54.2...3.68.0)

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

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

requirements-spotify.txt

@@ -1,3 +1,3 @@
 # Spotify related requirements
  # You need to install these with `sudo pip install --upgrade --force-reinstall -r requirements-spotify.txt`
- Mopidy-Iris==3.54.2
+ Mopidy-Iris==3.68.0