Bump flat and mocha

Bumps [flat](https://github.com/hughsk/flat) to 5.0.2 and updates ancestor dependency [mocha](https://github.com/mochajs/mocha). These dependencies need to be updated together.


Updates `flat` from 4.1.0 to 5.0.2
- [Release notes](https://github.com/hughsk/flat/releases)
- [Commits](https://github.com/hughsk/flat/compare/4.1.0...5.0.2)

Updates `mocha` from 6.2.3 to 10.2.0
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v6.2.3...v10.2.0)

---
updated-dependencies:
- dependency-name: flat
  dependency-type: indirect
- dependency-name: mocha
  dependency-type: direct:production
...

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

package.json

@@ -31,7 +31,7 @@
     "connect-busboy": "0.0.2",
     "express": "^4.17.1",
     "jquery": "^3.5.1",
-    "mocha": "^6.2.3",
+    "mocha": "^10.2.0",
     "morgan": "^1.10.0"
   },
   "devDependencies": {