Bump axios from 0.18.1 to 0.21.1 in /frontend

Bumps [axios](https://github.com/axios/axios) from 0.18.1 to 0.21.1.
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/v0.21.1/CHANGELOG.md)
- [Commits](https://github.com/axios/axios/compare/v0.18.1...v0.21.1)
Signed-off-by: Ndependabot[bot] <support@github.com>

frontend/package.json

@@ -12,7 +12,7 @@
     "build": "node build/build.js"
   },
   "dependencies": {
-    "axios": "^0.18.0",
+    "axios": "^0.21.1",
     "babel-polyfill": "^6.26.0",
     "babel-core": "^6.22.1",
     "babel-eslint": "^8.2.1",