Bump bcrypt from 3.0.8 to 5.0.0 in /backend

Bumps [bcrypt](https://github.com/kelektiv/node.bcrypt.js) from 3.0.8 to 5.0.0.
- [Release notes](https://github.com/kelektiv/node.bcrypt.js/releases)
- [Changelog](https://github.com/kelektiv/node.bcrypt.js/blob/master/CHANGELOG.md)
- [Commits](kelektiv/node.bcrypt.js@v3.0.8...v5.0.0)

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

Author: dependabot[bot]

backend/package.json

@@ -9,7 +9,7 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "bcrypt": "^3.0.6",
+    "bcrypt": "^5.0.0",
     "body-parser": "^1.19.0",
     "express": "^4.17.1",
     "jsonwebtoken": "^8.5.1",