build(deps-dev): bump @types/mocha from 7.0.2 to 8.0.3

Bumps [@types/mocha](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/mocha) from 7.0.2 to 8.0.3.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/mocha)

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

packages/azure-opentelemetry-exporter/package.json

@@ -24,7 +24,7 @@
     "url": "https://github.com/microsoft/opentelemetry-azure-monitor-js"
   },
   "devDependencies": {
-    "@types/mocha": "^7.0.2",
+    "@types/mocha": "^8.0.3",
     "@types/node": "^14.0.14",
     "@typescript-eslint/eslint-plugin": "^2.34.0",
     "c8": "^7.2.0",