missing typings for `styled`

__Expected behavior:__
A clear and concise description of what you expected to happen.

1. have a typescript + react project
2. install react-jss
3.
```
import { styled } from "react-jss";
```

I expected to be able to use `styled` without typescript errors

__Describe the bug:__
A clear and concise description of what happened instead of the expected behavior.

When I import `styled` I get the following error from `tsc`

```
'"../node_modules/react-jss/src"' has no exported member named 'styled'. Did you mean 'Styles'?
```

__Reproduction:__

Add a failing test to the suite and submit a PR. A test is even better than a fix.
Alternatively create a [codesandbox.io](https://codesandbox.io/) with the issue. Make it as minimal as possible as this will help us find the bug quicker.

https://codesandbox.io/s/react-jss-typescript-sokfq?file=/src/App.tsx

__Versions (please complete the following information):__
- jss: 10.7.1
- typescript 4.4.2
- Browser [e.g. chrome, safari]: chrome
- OS [e.g. Windows, macOS]: macOS
Feel free to add any additional versions which you may think are relevant to the bug.

__Managing expectations:__

Maintainers will not be fixing the problem you have unless they have it too, if you want it to get fixed:

1. Submit a PR with a failing test
2. Discuss a solution
3. Implement it

You can also do the first step only and wait for someone else to work on a fix. Anything is much better than nothing.