message: core: call postcssNested as a function
  per
diff: @@ -5,8 +5,7 @@ const postcssJS = require('postcss-js');
  const safeParser = require('postcss-safe-parser');
  const postcssConfig = { parser: postcssJS };
  -// any until issue resolved: https://github.com/postcss/postcss-nested/issues/88
  -const processor = postcss([postcssNested as any]);
  +const processor = postcss([postcssNested()]);
  export function cssObjectToAst(cssObject: CSSObject, sourceFile = '') {
  return processor.process(cssObject, { from: sourceFile, ...postcssConfig });
  