Bump axios in /firestore/solution-scheduled-backups (#197)

Bumps [axios](https://github.com/axios/axios) from 0.19.0 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@v0.19.0...v0.21.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

firestore/solution-scheduled-backups/package-lock.json

@@ -14,7 +14,7 @@
   "author": "Google, Inc.",
   "license": "Apache-2.0",
   "dependencies": {
-    "axios": "^0.19.0",
+    "axios": "^0.21.1",
     "dateformat": "^3.0.3",
     "express": "^4.17.1",
     "googleapis": "^42.0.0"