Update Jest

[klappradla]

This updates Jest (and babel-jest) to patch a security vulnerability on a package the old versions depended on: set-value.

See: https://github.com/advisories/GHSA-4jqc-8m5r-9rpr

With the update, we're now on Jest v27. On that version, Jest uses the node environment as the default environment for running tests in, instead of the slower jsdom environment. This means, tests which use the DOM API need to be switched back to run in the jsdom environment.

See https://jestjs.io/blog/2021/05/25/jest-27#flipping-defaults for details about the change.

For projects where only some tests require the DOM API, the Jest team recommends to still run the whole suite in the node environment (faster) and recommend the jsdom environment only for those tests where it's actually needed.

[klappradla]

Out of curiosity: Did you notice a difference in the time it takes to run the tests?

Haha, I was curious as well 🧐 - tried out two different setups:

1. Run in the node environment and only switch to jsdom where necessary (so essentially how it's set up in this PR)

2. Run everything in json

   Configured like this globally in the jest.config.js file: testEnvironment: 'jsdom'

Results: pretty much no difference 😉

1. Multi environment:

   $ time yarn test
   …
   Time:        5.691 s, estimated 6 s
   Ran all test suites.
   ✨  Done in 6.64s.
   yarn test  27.86s user 6.21s system 493% cpu 6.909 total

2. jsdom environment

   $ time yarn test
   …
   Time:        6.226 s
   Ran all test suites.
   ✨  Done in 7.14s.
   yarn test  31.29s user 6.93s system 515% cpu 7.413 total

🤷