chore(package): update ganache-cli to version 6.4.2

Closes #379

Author: greenkeeper[bot]

package.json

@@ -60,7 +60,7 @@
     "@types/web3": "1.0.18",
     "chai": "4.2.0",
     "coveralls": "3.0.2",
-    "ganache-cli": "6.3.0",
+    "ganache-cli": "6.4.2",
     "husky": "1.3.1",
     "lint-staged": "8.1.4",
     "mocha": "5.2.0",