Bump crossbeam-channel

Bumps the cargo group with 1 update in the /circ_blocks directory: [crossbeam-channel](https://github.com/crossbeam-rs/crossbeam).


Updates `crossbeam-channel` from 0.5.13 to 0.5.15
- [Release notes](https://github.com/crossbeam-rs/crossbeam/releases)
- [Changelog](https://github.com/crossbeam-rs/crossbeam/blob/master/CHANGELOG.md)
- [Commits](crossbeam-rs/crossbeam@crossbeam-channel-0.5.13...crossbeam-channel-0.5.15)

---
updated-dependencies:
- dependency-name: crossbeam-channel
  dependency-version: 0.5.15
  dependency-type: indirect
  dependency-group: cargo
...

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Author: dependabot[bot]