1. Run npm ci to install dependencies
  2. Run rm -rf node_modules/@jridgewell/trace-mapping to be 100% sure that it's not used
  3. Run npm run build
  4. Check the "sources" field in dist/bundle.js.map: it contains "webpack://sourcemap-test/./src/index.ts" and not "webpack://sourcemap-test/src/index.ts"