chore(package): update sinon to version 8.1.0

Closes #125

Author: greenkeeper[bot]

package.json

@@ -105,7 +105,7 @@
     "redux-logger": "^3.0.6",
     "remote-redux-devtools": "^0.5.12",
     "rimraf": "^2.6.1",
-    "sinon": "^6.0.0",
+    "sinon": "^8.1.0",
     "spectron": "^4.0.0",
     "style-loader": "^0.23.0",
     "stylelint": "^9.1.1",