chore(package): update sinon to version 6.0.0

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "cz-conventional-changelog": "^2.0.0",
     "nyc": "^12.0.1",
     "semantic-release": "^15.0.0",
-    "sinon": "^5.0.1",
+    "sinon": "^6.0.0",
     "xo": "^0.21.0"
   },
   "engines": {