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


return createSandboxBundle(defines, {
        disableVersionInfo: true,
      }).pipe(gulp.dest(sandboxDir));
    }
  )
);
gulp.task(
  "server",
  gulp.parallel(
    function watchDevCSS() {
      gulp.watch(
        ["web/*.css", "web/images/*"],
        { ignoreInitial: false },
        gulp.series("dev-css")
      );
    },
    function watchDevFitCurve() {
      gulp.watch(
        ["src/display/editor/*"],
        { ignoreInitial: false },
        gulp.series("dev-fitCurve")
      );
    },
    function watchDevSandbox() {
      gulp.watch(
        [
          "src/pdf.{sandbox,sandbox.external,scripting}.js",
          "src/scripting_api/*.js",
          "src/shared/scripting_utils.js",
          "external/quickjs/*.js",