chore(package): update sinon to version 7.5.0

Closes #14

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "mocha": "^5.0.5",
     "pkgcfg": "^0.9.1",
     "rimraf": "^2.6.2",
-    "sinon": "^4.4.8",
+    "sinon": "^7.5.0",
     "temp": "^0.8.3"
   },
   "dependencies": {