This updates React, TypeScript, and some other node packages (but not
everything).
A couple of notes:
- `enzyme-adapter-react-16` does not have a React 17 equivalent yet, so I
switched to the fork `@wojtekmaj/enzyme-adapter-react-17`
- A bunch of tests are still failing because I think in the enzyme testing
environment, a browser API (`ResizeObserver`) is missing, and maybe for other
reasons. This needs to be explored + fixed.
- The TypeScript update introduced more stringent rules, which required fixing
up a bunch of pieces of code a bit.
- The `use-media` package doesn't work with React 17 yet, so I just built our
own minimal `useMedia` hook instead (just a couple of lines).
- I commented out part of the code in `withStartingIndicator.tsx` because it
fails the now-stricter lint checks. It needs to be fixed (and not commented
out).
Signed-off-by: Julius Volz <julius.volz@gmail.com>
