Bump chisel3 from `759de02e` to `b15a1bc7` (#207)

Bumps [chisel3](https://github.com/freechipsproject/chisel3) from `759de02e` to `b15a1bc7`.
- [Release notes](https://github.com/freechipsproject/chisel3/releases)
- [Commits](https://github.com/freechipsproject/chisel3/compare/759de02ec2b8e21d0035508d1ea47b560f706d84...b15a1bc7a1b6be06952b5407c7ba043b434e1268

)

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

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