message: fix: winPath problem in umiExports
diff: import { IApi } from '@umijs/types';
  -import { lodash } from '@umijs/utils';
  +import { lodash, winPath } from '@umijs/utils';
  import assert from 'assert';
  const reserveLibrarys = ['umi']; // reserve library
  @@ -66,7 +66,9 @@ export function generateExports({
  return `${specifier.local} as ${specifier.exported}`;
  }
  });
  - return `export { ${specifiersStrArr.join(', ')} } from '${item.source}';`;
  + return `export { ${specifiersStrArr.join(', ')} } from '${winPath(
  + item.source,
  + )}';`;
  }
  export default function(api: IApi) {
  