build(deps): bump third_party/prjxray from `a1f3ae2` to `731fbce` (#3841)

Bumps [third_party/prjxray](https://github.com/f4pga/prjxray) from `a1f3ae2` to `731fbce`.
- [Commits](https://github.com/f4pga/prjxray/compare/a1f3ae28a732c5dcb7d72ee0d37407a757ed4666...731fbcecd2878656af14465801c80e2a34057876)

---
updated-dependencies:
- dependency-name: third_party/prjxray
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/prjxray b/third_party/prjxray
index a1f3ae2..731fbce 160000
--- a/third_party/prjxray
+++ b/third_party/prjxray
@@ -1 +1 @@
-Subproject commit a1f3ae28a732c5dcb7d72ee0d37407a757ed4666
+Subproject commit 731fbcecd2878656af14465801c80e2a34057876