chore(deps-dev): bump sinon from 7.5.0 to 8.1.1

Bumps [sinon](https://github.com/sinonjs/sinon) from 7.5.0 to 8.1.1.
- [Release notes](https://github.com/sinonjs/sinon/releases)
- [Changelog](https://github.com/sinonjs/sinon/blob/master/CHANGELOG.md)
- [Commits](sinonjs/sinon@v7.5.0...v8.1.1)

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

package.json

@@ -46,7 +46,7 @@
     "hexo-fs": "^2.0.0",
     "mocha": "^6.1.4",
     "nyc": "^15.0.0",
-    "sinon": "^7.3.2",
+    "sinon": "^8.1.1",
     "supertest": "^4.0.2",
     "uuid": "^3.3.2"
   },