Bump third_party/prjxray from `931576a` to `6151829`
Bump third_party/prjxray from `931576a` to `6151829`

Bumps [third_party/prjxray](https://github.com/SymbiFlow/prjxray) from `931576a` to `6151829`.
- [Release notes](https://github.com/SymbiFlow/prjxray/releases)
- [Commits](https://github.com/SymbiFlow/prjxray/compare/931576a770a6dec5ca91c8d3368be59a98c19817...61518291018a09b25e003ecbc70a924dba3118f5)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
SymbiFlow/symbiflow-arch-defs,SymbiFlow/symbiflow-arch-defs