fix(rollup): handle array format for rollup.alias.entries option

[zoeyzhao19]

rollop alias option from config file like

rollup: {
  alias: {
      entries: [
        {
          find: '@shared/types',
          replacement: path.resolve(projectRootDir, 'src/shared/types'),
        },
      ],
    }
}

entries above wouldn't get the right alias config since unbuild does not handle this scene.
This PR is related to #221

[pi0]

Thanks!