add to the funding field in the package.json

[bjohansebas]

The funding field was added to the Express repo a while ago. It would be good to include it in the other important repositories of the Express project.

This was attempted in expressjs/compression#210, but until there is an agreement within the team, it can't be added to the other repositories. I'm opening this so it doesn't get forgotten.

[wesleytodd]

Yeah, I agree we should do this now that we agreed to land it and have published the main one in v5. I wonder what we need to do to agree, just let this sit for a bit and ask for dissent? I don't think this needs any real documentation on the decision, but maybe others disagree?

[wesleytodd]

We agree this is good, next up:

1. Make a list of repos to add it to
2. Open PRs to each
3. Merge the PRs