build(deps): Bump @openzeppelin/contracts in /packages/payment-processor

Bumps [@openzeppelin/contracts](https://github.com/OpenZeppelin/openzeppelin-contracts) from 4.7.3 to 4.9.3.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-contracts/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/CHANGELOG.md)
- [Commits](OpenZeppelin/openzeppelin-contracts@v4.7.3...v4.9.3)

---
updated-dependencies:
- dependency-name: "@openzeppelin/contracts"
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

packages/payment-processor/package.json

@@ -39,7 +39,7 @@
     "test:watch": "yarn test --watch"
   },
   "dependencies": {
-    "@openzeppelin/contracts": "4.7.3",
+    "@openzeppelin/contracts": "4.9.3",
     "@requestnetwork/currency": "0.9.0",
     "@requestnetwork/payment-detection": "0.36.0",
     "@requestnetwork/smart-contracts": "0.29.0",