message: packages/cli: update prettier config in plugin template
diff: },
  "devDependencies": {
  "@backstage/cli": "^{{version}}",
  + "@spotify/prettier-config": "^7.0.0",
  "lerna": "^3.20.2",
  "patch-package": "^6.2.2",
  "prettier": "^1.19.1"
  + },
  + "prettier": "@spotify/prettier-config",
  + "lint-staged": {
  + "*.{js,jsx,ts,tsx}": [
  + "eslint --fix",
  + "prettier --write"
  + ],
  + "*.{json,md}": [
  + "prettier --write"
  + ]
  }
  }
  