chore(deps): update eslint monorepo to v9.21.0

Author: renovate[bot]

package-lock.json

@@ -26,7 +26,7 @@
     "packages/*"
   ],
   "devDependencies": {
-    "@eslint/js": "9.20.0",
+    "@eslint/js": "9.21.0",
     "@serialport/bindings-cpp": "13.0.0",
     "@stylistic/eslint-plugin": "4.0.1",
     "@tsconfig/node18": "18.2.4",
@@ -40,7 +40,7 @@
     "chai-subset": "1.6.0",
     "esbuild": "0.25.0",
     "esbuild-register": "3.6.0",
-    "eslint": "9.20.1",
+    "eslint": "9.21.0",
     "eslint-plugin-mocha": "10.5.0",
     "globals": "15.14.0",
     "lerna": "7.4.2",