fix: add .js extension for ES Module

Author: amanabiy

lib/dev-pages-utils/permutations.js

@@ -1,6 +1,6 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
-import flatten from "lodash/flatten";
+import flatten from "lodash/flatten.js";
 export function createPermutations(permutations) {
     return flatten(permutations.map(set => doCreatePermutations(set)));
 }

src/dev-pages-utils/permutations.tsx

@@ -1,6 +1,6 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
-import flatten from "lodash/flatten";
+import flatten from "lodash/flatten.js";
 
 export type ComponentPermutations<Props> = {
   [prop in keyof Props]: ReadonlyArray<Props[prop]>;