Bump mocha from 6.2.2 to 7.0.0

Bumps [mocha](https://github.com/mochajs/mocha) from 6.2.2 to 7.0.0.
- [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...v7.0.0)

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

package.json

@@ -80,7 +80,7 @@
     "karma-webpack": "^4.0.0-rc.2",
     "loglevelnext": "^3.0.1",
     "marked": "0.8.0",
-    "mocha": "6.2.2",
+    "mocha": "7.0.0",
     "ol-mapbox-style": "^5.0.2",
     "pixelmatch": "^5.1.0",
     "pngjs": "^3.4.0",