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 6.2.2 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/v6.2.2...v10.2.0)

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

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

package.json

@@ -62,7 +62,7 @@
   "devDependencies": {
     "@types/mocha": "^2.2.32",
     "@types/node": "^6.0.40",
-    "mocha": "^6.2.2",
+    "mocha": "^10.2.0",
     "typescript": "^2.0.3",
     "vscode": "^1.0.0"
   },