Bump bbv from 6144e21 to f4caa05

Bumps [bbv](https://github.com/mit-plv/bbv) from `6144e21` to `f4caa05`.
- [Release notes](https://github.com/mit-plv/bbv/releases)
- [Commits](mit-plv/bbv@6144e21...f4caa05)

---
updated-dependencies:
- dependency-name: bbv
  dependency-type: direct:production
...

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