chore: updating sinon package

Author: jarrodek

package-lock.json

@@ -69,7 +69,7 @@
     "glob": "^7.1.6",
     "lit-element": "^2.2.1",
     "mocha": "^6.2.1",
-    "sinon": "^7.4.2",
+    "sinon": "^8.0.1",
     "spectron": "^9.0.0",
     "web-animations-js": "^2.3.2"
   },