Update sinon to the latest version 🚀 (#128)

## The devDependency [sinon](https://github.com/sinonjs/sinon) was updated from `6.3.5` to `7.2.3`.
This version is **not covered** by your **current version range**.

If you don’t accept this pull request, your project will work just like it did before. However, you might be missing out on a bunch of new features, fixes and/or performance improvements from the dependency update.

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[Find out more about this release](https://github.com/sinonjs/sinon).

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package-lock.json

@@ -33,7 +33,7 @@
     "eslint-config-xo-space": "^0.19.0",
     "jest": "^23.2.0",
     "mem-fs": "^1.0.0",
-    "sinon": "^6.0.1"
+    "sinon": "^7.2.3"
   },
   "jest": {
     "collectCoverage": true,