No linting inside styled-is and media mixin

[karolisgrinkevicius]

Hi. Not sure this issue might belong to stylelint-processor-styled-components but in fact linter ignores css within styled-is and media mixins described here.

Please see the code snippet below which represents the parts that not working against linter even though configuration is setup correctly and works well if NOT wrapped into media mixin or styled-is:

import styled from 'styled-components';
import is from 'styled-is';
import { media } from 'utils/media';

export const MyStyledComponent = styled.div`
  nonExistingProperty: 'nonExistingValue'; /* Works! ✅ */

  ${is('active')`
    nonExistingProperty: 'nonExistingValue'; /* Doesn't work! 🚫 */
  `};
  
  ${media.sm`
    nonExistingProperty: 'nonExistingValue'; /* Doesn't work! 🚫 */
  `};
`;

Used dependencies

• stylelint 9.4.0
• stylelint-processor-styled-components 1.3.2
• styled-components 3.3.3
• styled-is 1.1.3

[chinesedfan]

Please refer to #182. It is hard to lint interpolations now.