In Webpack 5, the [recommended way](https://webpack.js.org/guides/web-workers/) to create a web worker is

```ts
new Worker(new URL('./worker.js', import.meta.url));
```

Could we update\* the [`pdfjs-dist/webpack` entrypoint](https://github.com/mozilla/pdfjs-dist/blob/master/webpack.js) to use this syntax instead of the legacy `worker-loader`? One of the Webpack contributors told me that `worker-loader` uses "magic" and can cause issues.

\* To maintain compatibility with people still using Webpack 4, we should probably introduce a new entrypoint called `pdfjs-dist/webpack5` (or something like that) rather than changing the existing entrypoint.

Can attempt a PR if you would like.

Closely-related: https://github.com/mozilla/pdf.js/issues/15302


console.log("Skipping invalid locale: " + locale);
      continue;
    }
    mkdirp.sync(VIEWER_LOCALE_OUTPUT + "/" + locale);
    locales.push(locale);
    if (checkFile(dirPath + "/viewer.properties")) {
      viewerOutput +=
        "[" +
        locale +
        "]\n" +
        "@import url(" +
        locale +
        "/viewer.properties)\n\n";
    }
  }
  return merge([
    createStringSource("locale.properties", viewerOutput).pipe(
      gulp.dest(VIEWER_LOCALE_OUTPUT)
    ),
    gulp
      .src(L10N_DIR + "/{" + locales.join(",") + "}/viewer.properties", {
        base: L10N_DIR,
      })
      .pipe(gulp.dest(VIEWER_LOCALE_OUTPUT)),
  ]);
});
gulp.task("cmaps", function (done) {
  const CMAP_INPUT = "external/cmaps";
  const VIEWER_CMAP_OUTPUT = "external/bcmaps";
  console.log();