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


const preprocessor2 = require("./external/builder/preprocessor2.js");
  const licenseHeader = fs.readFileSync("./src/license_header.js").toString();
  const GLOBALS = "/* eslint-disable */\n";
  const MODIFICATION_WARNING =
    "//\n// THIS FILE IS GENERATED AUTOMATICALLY, DO NOT EDIT MANUALLY!\n//\n";
  const bundleDefines = builder.merge(DEFINES, {
    DEFAULT_PREFERENCES: getDefaultPreferences("mozcentral/"),
  });
  content = preprocessor2.preprocessPDFJSCode(
    {
      rootPath: __dirname,
      defines: bundleDefines,