Bump hardhat from 2.16.1 to 2.21.0 in /proxy

Bumps [hardhat](https://github.com/nomiclabs/hardhat) from 2.16.1 to 2.21.0.
- [Release notes](https://github.com/nomiclabs/hardhat/releases)
- [Commits](https://github.com/nomiclabs/hardhat/compare/hardhat@2.16.1...hardhat@2.21.0)

---
updated-dependencies:
- dependency-name: hardhat
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

proxy/package.json

@@ -34,7 +34,7 @@
         "ethereumjs-util": "^7.1.5",
         "ethers": "^5.7.2",
         "ethers-eip712": "^0.2.0",
-        "hardhat": "2.11.0 - 2.16.1",
+        "hardhat": "2.11.0 - 2.21.1",
         "path": "^0.12.7"
     },
     "devDependencies": {