Bump chisel3 from `26b784c3` to `66d891bd` (#171)

Bumps [chisel3](https://github.com/freechipsproject/chisel3) from `26b784c3` to `66d891bd`.
- [Release notes](https://github.com/freechipsproject/chisel3/releases)
- [Commits](https://github.com/freechipsproject/chisel3/compare/26b784c3c91a1766c6492f09bb54688543bde1b0...66d891bd39d00973289babc26474e602570d4bca

)

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

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