chore(package): update sinon to version 7.4.0

Closes #62

Author: greenkeeper[bot]

package.json

@@ -82,7 +82,7 @@
     "rimraf": "2.5.4",
     "rollup": "0.38.1",
     "rollup-plugin-babel": "2.7.1",
-    "sinon": "1.17.7",
+    "sinon": "7.4.0",
     "sinon-chai": "2.8.0",
     "webpack": "1.14.0"
   }