Bump music21-rs

Bumps the rust-dependencies group with 1 update in the / directory: [music21-rs](https://github.com/float3/music21-rs).


Updates `music21-rs` from `adbeeee` to `6bce2ba`
- [Release notes](https://github.com/float3/music21-rs/releases)
- [Commits](float3/music21-rs@adbeeee...6bce2ba)

---
updated-dependencies:
- dependency-name: music21-rs
  dependency-version: 9067392a789490a34a6b0066dec96dc239ac0c57
  dependency-type: direct:production
  dependency-group: rust-dependencies
...

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Author: dependabot[bot]