message: fix: include ui.css in ui package
  Details
  Similar to fixes a bug that is preventing the ui package css file from being included when the package is published
  Motivation
  Include `ui.css` in the published package
  Context
  Verified with `npm pack` that the `ui.css` file is included in the package
diff: {
  "name": "accessibility-insights-ui",
  - "version": "0.1.2",
  + "version": "0.1.3",
  "description": "Accessibility Insights UI Components",
  "license": "MIT",
  "files": [
  "../../LICENSE",
  - "./drop",
  + "drop",
  "README.md"
  ],
  "main": "drop/index.js",
  