Bump axios from 0.18.1 to 0.21.2 in /ui

Bumps [axios](https://github.com/axios/axios) from 0.18.1 to 0.21.2.
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/v0.21.2/CHANGELOG.md)
- [Commits](axios/axios@v0.18.1...v0.21.2)

---
updated-dependencies:
- dependency-name: axios
  dependency-type: direct:production
...

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

Author: dependabot[bot]

ui/package-lock.json

@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "async": "^2.6.3",
-    "axios": "^0.18.1",
+    "axios": "^0.21.2",
     "bibtex": "^0.9.0",
     "bootstrap-vue": "^2.21.2",
     "brace": "^0.11.1",