update dependencies

[romainmenke]

With the current setup using npm workspaces for the polyfills I didn't take build tools for polyfills into account as we didn't have any. And polyfills tend to be self contained and have no dependencies.

However URL and IteratorHelpers now have a build tool to prepare the polyfills for older browsers.

Build tools always have incredibly deep and complex dependency graphs.

A side effect of introducing build tools for polyfills is that running npm update now has unwanted side effects as it will update those deeply nested dependencies even when direct dependency (e.g. browserify, babelify, ...) has a pinned version.

I expect this PR to change, even when it contains a few minor changes to transitive dependencies. This shows the brittleness of the current approach.

---

I am also a bit concerned that we are giving up a lot of control over the final result and the quality thereof.

These tools are known for adding a bunch of bloat which often isn't needed.

Manually written code for older browsers, all in a single file, will always be better and smaller. Ideally we don't have any build tools for polyfills.

I know that this is more work and that we then lose the connection to upstream maintainers. But I do think this is best for end users.