chore(package): update sinon to version 7.4.1

Closes #248

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "memory-card": "^0.6.8",
     "qrcode-terminal": "^0.12.0",
     "shx": "^0.3.1",
-    "sinon": "^6.0.1",
+    "sinon": "^7.4.1",
     "ts-node": "^7.0.0",
     "tslint": "^5.11.0",
     "tslint-config-standard": "^8.0.1",