message: Bump version in lib/package.json
diff: {
  "name": "@material-ui/pickers",
  - "version": "4.0.0-alpha.11",
  + "version": "4.0.0-alpha.12",
  "private": true,
  "description": "React components, that implements material design pickers for material-ui v4",
  "main": "./src/index.ts",
  