Broken forum link in README.md

[blackblather]

The forum link in the readme file leads to a 404

[two-trick-pony-NL]

👋 Hey @blackblather

I work at bunq and am currently reviewing the bunq API docs, open issues and SDK’s and came across your issue. I know it’s been open for a while, and I’d love to understand how it’s impacting you. Beyond the obvious -fixing this issue-, what else could we do to improve your experience with our API?

If you want to share your thoughts on how we can improve on our public API:

📅 I'd love to schedule a 15 minute interview to understand your needs through: Calendly
💬 Or if you don't have time for a call, you can give us some general feedback through this form

Your feedback will go straight to our product team! 🚀

[two-trick-pony-NL]

Created a pull request to update the form link.