chore: bump ethers in /examples/relayer-call-contract-function

Bumps [ethers](https://github.com/ethers-io/ethers.js) from 5.7.2 to 6.16.0.
- [Release notes](https://github.com/ethers-io/ethers.js/releases)
- [Changelog](https://github.com/ethers-io/ethers.js/blob/main/CHANGELOG.md)
- [Commits](ethers-io/ethers.js@v5.7.2...v6.16.0)

---
updated-dependencies:
- dependency-name: ethers
  dependency-version: 6.16.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

examples/relayer-call-contract-function/package.json

@@ -11,6 +11,6 @@
   "dependencies": {
     "@openzeppelin/defender-sdk": "1.15.0",
     "dotenv": "^16.3.1",
-    "ethers": "^6.15.0"
+    "ethers": "^6.16.0"
   }
 }