Specify rollup v0.60+ as peer dependency (#19)
Specify rollup v0.60+ as peer dependency (#19)

- using same trick as rollup-plugin-babel:
  https://github.com/rollup/rollup-plugin-babel/blob/5168424e7d9e28e612e26c159c39862d8c4727ab/package.json#L38
  in order to make sure that correct version of rollup is used:
  https://rollupjs.org/guide/en#deprecated
btd/rollup-plugin-visualizer,btd/rollup-plugin-visualizer