Bump firrtl from `b6fd24c` to `552edd6` (#158)

Bumps [firrtl](https://github.com/freechipsproject/firrtl) from `b6fd24c` to `552edd6`.
- [Release notes](https://github.com/freechipsproject/firrtl/releases)
- [Commits](https://github.com/freechipsproject/firrtl/compare/b6fd24cfea04e6db019fde61dba349dbfe45bf9c...552edd6b8478a6a882fd592efbe98ecfecf30c0d

)

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

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