[Tests] use npm audit instead of aud

Author: ljharb

package.json

@@ -13,7 +13,7 @@
     "postlint": "npm run type-check",
     "pretest": "npm run lint",
     "test": "npm run unit-test",
-    "posttest": "aud --production",
+    "posttest": "npx npm@'>= 10.2' audit --production",
     "type-check": "tsc",
     "unit-test": "istanbul cover node_modules/mocha/bin/_mocha tests/lib/**/*.js tests/util/**/*.js tests/index.js tests/flat-config.js",
     "update:eslint-docs": "eslint-doc-generator"
@@ -55,7 +55,6 @@
     "@types/estree": "0.0.52",
     "@types/node": "^4.9.5",
     "@typescript-eslint/parser": "^2.34.0 || ^3.10.1 || ^4.0.0 || ^5.0.0",
-    "aud": "^2.0.5",
     "babel-eslint": "^8 || ^9 || ^10.1.0",
     "eslint": "^3 || ^4 || ^5 || ^6 || ^7 || ^8 || ^9.7",
     "eslint-config-airbnb-base": "^15.0.0",