chore(package): update sinon-chai to version 3.5.0

Closes #73

Author: greenkeeper[bot]

package.json

@@ -66,7 +66,7 @@
     "postcss": "^6.0.7",
     "postcss-modules": "^1.0.0",
     "sinon": "^4.0.1",
-    "sinon-chai": "^2.8.0",
+    "sinon-chai": "^3.5.0",
     "string-hash": "^1.1.1"
   },
   "peerDependencies": {