fix(package): update bcrypt to version 4.0.0

Closes #97

Author: greenkeeper[bot]

package.json

@@ -5,7 +5,7 @@
   "main": "server.js",
   "dependencies": {
     "@paypal/checkout-server-sdk": "^1.0.1",
-    "bcrypt": "3.0.4",
+    "bcrypt": "4.0.0",
     "body-parser": "1.18.3",
     "chai": "4.2.0",
     "chai-http": "4.3.0",