[react-jss] No critical css generated on server

Expected behavior:

const sheets = new SheetsRegistry();
const html = ReactDOM.renderToString(
  <JssProvider registry={sheets}>
    <App />
  </JssProvider>
);
const css = sheets.toString();

css should not be empty.

Describe the bug: It seems that SheetsRegistry return empty string in toString method because no stylesheet is attached. Example repo: https://github.com/bungu/jss-no-critical-css

It works in v9

Versions (please complete the following information):

• JSS: v10.0.0-alpha.13
• React-JSS: v10.0.0-alpha.6

$ npm list jss react-jss
jss-no-critical-css@0.1.0 ~/sandbox/jss-no-critical-css
└─┬ react-jss@10.0.0-alpha.6
  └── UNMET PEER DEPENDENCY jss@10.0.0-alpha.13

npm ERR! peer dep missing: jss@10.0.0-alpha.3, required by jss-preset-default@10.0.0-alpha.7

[kof]

Fixed, will be released in 10.0.0-alpha.14

[oliviertassinari]

Well done 😃