fix: convert project to ESM to support @actions/core v3

Co-authored-by: felickz <1760475+felickz@users.noreply.github.com>

Author: Copilot

__tests__/main.test.ts

@@ -1,4 +1,4 @@
-import {normalizeCweId} from '../src/utils'
+import {normalizeCweId} from '../src/utils.js'
 
 describe('main', () => {
   it('placeholder test', () => {