Bump third_party/prjxray from `78c47ab` to `ef63708`
Bump third_party/prjxray from `78c47ab` to `ef63708`

Bumps [third_party/prjxray](https://github.com/SymbiFlow/prjxray) from `78c47ab` to `ef63708`.
- [Release notes](https://github.com/SymbiFlow/prjxray/releases)
- [Commits](https://github.com/SymbiFlow/prjxray/compare/78c47ab82b65ebd1878437a418f595ee14415076...ef6370894ba8c6e1bcfd583b7204abc3788c8648)

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