Bump music21 from 8.1.0 to 9.5.0

Bumps [music21](https://github.com/cuthbertLab/music21) from 8.1.0 to 9.5.0.
- [Release notes](https://github.com/cuthbertLab/music21/releases)
- [Commits](cuthbertLab/music21@v8.1.0...v9.5.0)

---
updated-dependencies:
- dependency-name: music21
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -1,3 +1,3 @@
-music21==8.1.0
+music21==9.5.0
 scipy==1.10.1; python_version < '3.9'
 scipy==1.13.0; python_version >= '3.9'