message: Build testbed dependencies.
diff: "private": true,
  "license": "MIT",
  "scripts": {
  + "prebuild": "rush build -t imodeljs-core-testbed",
  "build": "tsc 1>&2 && npm run copy:frontendpublic && npm run copy:testpublic && npm run webpack:frontend",
  "clean": "rimraf lib backend/lib frontend/lib package-deps.json",
  "copy:frontendpublic": "cpx ../core/frontend/src/public/**/* ./lib/backend/public",
  