Bump yosys from 672375e to 6f1ca68

Bumps [yosys](https://github.com/YosysHQ/yosys) from `672375e` to `6f1ca68`.
- [Release notes](https://github.com/YosysHQ/yosys/releases)
- [Commits](YosysHQ/yosys@672375e...6f1ca68)

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

Signed-off-by: dependabot[bot] <[email protected]>