Bump firrtl from `552edd6` to `7ceebcf` (#162)

Bumps [firrtl](https://github.com/freechipsproject/firrtl) from `552edd6` to `7ceebcf`.
- [Release notes](https://github.com/freechipsproject/firrtl/releases)
- [Commits](https://github.com/freechipsproject/firrtl/compare/552edd6b8478a6a882fd592efbe98ecfecf30c0d...7ceebcfffd1bbd823681217ee8629080bd03c79b

)

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

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