fix(package): update mocha to version 7.1.0

Closes #37

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "@types/sinon": "^7.5.0",
     "@types/sinon-chai": "^3.2.3",
     "chai": "^4.2.0",
-    "mocha": "^6.2.2",
+    "mocha": "^7.1.0",
     "sinon": "^7.5.0",
     "sinon-chai": "^3.3.0"
   },