Build(deps): Bump yosys-f4pga-plugins from 6689e20 to c8d2d14

Bumps [yosys-f4pga-plugins](https://github.com/chipsalliance/yosys-f4pga-plugins) from `6689e20` to `c8d2d14`.
- [Commits](chipsalliance/yosys-f4pga-plugins@6689e20...c8d2d14)

---
updated-dependencies:
- dependency-name: yosys-f4pga-plugins
  dependency-type: direct:production
...

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