fix: array.prototype.flatmap as prod dependency

package.json

@@ -59,7 +59,6 @@
     "@eslint/import-test-order-redirect-scoped": "file:./tests/files/order-redirect-scoped",
     "@test-scope/some-module": "file:./tests/files/symlinked-module",
     "@typescript-eslint/parser": "^2.23.0 || ^3.3.0 || ^4.29.3 || ^5.10.0",
-    "array.prototype.flatmap": "^1.3.0",
     "babel-cli": "^6.26.0",
     "babel-core": "^6.26.3",
     "babel-eslint": "=8.0.3 || ^8.2.6",
@@ -104,6 +103,7 @@
   "dependencies": {
     "array-includes": "^3.1.6",
     "array.prototype.flat": "^1.3.1",
+    "array.prototype.flatmap": "^1.3.0",    
     "debug": "^3.2.7",
     "doctrine": "^2.1.0",
     "eslint-import-resolver-node": "^0.3.7",