Update the runnable sandbox.

[DaddyWarbucks]

Codesandbox no longer handles tests the way that they used to. The "Test Panel" is no longer available on "Sandboxes" and is only available on "Devboxes". I don't use the product enough to know the difference.

Therefore this link is no longer really useful
https://codesandbox.io/s/yup-test-case-gg1g1

See: https://codesandbox.io/docs/learn/sandboxes/faq#where-can-i-find-the-tests-tab

[jquense]

wanna PR an update to use stackblitz?

[DaddyWarbucks]

I am indifferent on which platform is used. I just noticed it while creating another issue. I will take a look at "Devboxes" and see if they support test similar to how it used to be, that was nice to have a test runner already setup.

I'm happy to put something basic together and open a PR. Also open to other suggestions.