Bump chisel3 from `bb3ef96d` to `7ff5fd4a` (#336)

Bumps [chisel3](https://github.com/freechipsproject/chisel3) from `bb3ef96d` to `7ff5fd4a`.
- [Release notes](https://github.com/freechipsproject/chisel3/releases)
- [Commits](https://github.com/freechipsproject/chisel3/compare/bb3ef96d8911dbba4e22926ad4ce71eb8ab0d869...7ff5fd4aa7dc01099614da9cc3b72d53f61d1cdb

)

---
updated-dependencies:
- dependency-name: chisel3
  dependency-type: direct:production
...

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

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