Bump @openzeppelin/contracts-upgradeable in /packages/contracts

Bumps [@openzeppelin/contracts-upgradeable](https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable) from 4.8.3 to 4.9.6.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable/blob/master/CHANGELOG.md)
- [Commits](OpenZeppelin/openzeppelin-contracts-upgradeable@v4.8.3...v4.9.6)

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

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

packages/contracts/package.json

@@ -19,7 +19,7 @@
   },
   "dependencies": {
     "@ethereum-attestation-service/eas-contracts": "1.7.1",
-    "@openzeppelin/contracts-upgradeable": "4.8.3"
+    "@openzeppelin/contracts-upgradeable": "4.9.6"
   },
   "devDependencies": {
     "@types/prettier": "2",