Bump chisel3 from `10e9697e` to `6c640932` (#268)

Bumps [chisel3](https://github.com/freechipsproject/chisel3) from `10e9697e` to `6c640932`.
- [Release notes](https://github.com/freechipsproject/chisel3/releases)
- [Commits](https://github.com/freechipsproject/chisel3/compare/10e9697e132a1e0dd1f30ff40ae9119509efaeaf...6c6409328034e06c4b722e87022029b287e9c90c

)

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

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