Bump axios from 0.19.2 to 0.21.1 in /frontend

Bumps [axios](https://github.com/axios/axios) from 0.19.2 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](axios/axios@v0.19.2...v0.21.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

frontend/package-lock.json

@@ -10,7 +10,7 @@
     "build": "cross-env NODE_ENV=production webpack --progress --hide-modules"
   },
   "dependencies": {
-    "axios": "^0.19.2",
+    "axios": "^0.21.1",
     "jspdf": "^2.3.1",
     "showdown": "^1.9.1",
     "vue": "^2.5.11",