Bump mocha from 6.2.3 to 8.1.2

Bumps [mocha](https://github.com/mochajs/mocha) from 6.2.3 to 8.1.2.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](mochajs/mocha@v6.2.3...v8.1.2)

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

package.json

@@ -28,7 +28,7 @@
   },
   "devDependencies": {
     "chai": "^4.2.0",
-    "mocha": "^6.2.2",
+    "mocha": "^8.1.2",
     "nyc": "^14.1.1"
   }
 }