Update the `busboy` dependency to v1
The `busboy` v1 update has a lot of great improvements, and importantly fixes this security flaw:

https://github.com/advisories/GHSA-wm7h-9275-46v2

Unfortunately, it also introduces a bug where the file size limit is 1 byte off:

https://github.com/mscdex/busboy/issues/297

If we were to update the `graphql-upload` dependency `busboy` to v1 with that bug, imagine how many apps have public facing labels on file upload inputs saying things like "max 4 MB file size" and users would try to upload an exactly 4 MB file and it would be erroring. To avoid having to update our front ends to say "max 3.999999 MB" we would have to change our `graphql-upload` `maxFileSize` config in GraphQL APIs to be the real limit we want + 1. But then, if this `busboy` bug is fixed in a patch release, suddenly files 1 byte too big will start being accepted which could have who knows what problems further down the line in our systems depending how the files are used.

We might be forced to publish a major release of `graphql-upload` that only bumps `busboy` to v1, but with a big warning in the changelog entry that explains this outstanding `busboy` bug and that people should be aware of the dilemma and deal with it as best as they can.