Bump mocha from 8.3.2 to 8.4.0

Bumps [mocha](https://github.com/mochajs/mocha) from 8.3.2 to 8.4.0.
- [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/v8.3.2...v8.4.0)

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

package.json

@@ -92,7 +92,7 @@
     "karma-webpack": "^5.0.0",
     "loglevelnext": "^4.0.1",
     "marked": "2.0.3",
-    "mocha": "8.3.2",
+    "mocha": "8.4.0",
     "pixelmatch": "^5.1.0",
     "pngjs": "^6.0.0",
     "proj4": "2.7.2",