message: Update version to rc.8
diff: {
  "name": "material-ui-pickers",
  - "version": "1.0.0-rc.7",
  + "version": "1.0.0-rc.8",
  "private": true,
  "description": "React components, that implements material design pickers for material-ui v1",
  "main": "build/dist/material-ui-pickers.cjs.js",
  