Update dependency solhint to v6

Author: renovate[bot]

package-lock.json

@@ -85,7 +85,7 @@
     "prettier-plugin-solidity": "^2.0.0",
     "rimraf": "^6.0.0",
     "semver": "^7.3.5",
-    "solhint": "^5.0.0",
+    "solhint": "^6.0.0",
     "solhint-plugin-openzeppelin": "file:scripts/solhint-custom",
     "solidity-ast": "^0.4.50",
     "solidity-coverage": "^0.8.14",