Bump firrtl from `97dbe29` to `4181e92` (#179)

Bumps [firrtl](https://github.com/freechipsproject/firrtl) from `97dbe29` to `4181e92`.
- [Release notes](https://github.com/freechipsproject/firrtl/releases)
- [Commits](https://github.com/freechipsproject/firrtl/compare/97dbe29eae140a4ef0e241681f128ba8a7633b2e...4181e92732f616d4c58409cd59ae782f11967d45

)

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

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

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