message: webpack-plugin: add missing optimizer dependency
diff: "dependencies": {
  "@stylable/module-utils": "^2.0.1",
  "@stylable/node": "^2.0.1",
  + "@stylable/optimizer": "^2.0.0",
  "@stylable/runtime": "^2.0.0",
  "find-config": "^1.0.0",
  "webpack-sources": "^1.3.0"
  