Bump prettier from 1.19.1 to 2.0.2 in /app

Bumps [prettier](https://github.com/prettier/prettier) from 1.19.1 to 2.0.2.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@1.19.1...2.0.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

app/package.json

@@ -38,7 +38,7 @@
     "immutable": "4.0.0-rc.12",
     "jquery": "3.4.1",
     "popper.js": "1.16.1",
-    "prettier": "1.19.1",
+    "prettier": "2.0.2",
     "react": "16.13.1",
     "react-bootstrap": "1.0.0",
     "react-dom": "16.13.0",