fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:lodash:20180130

Latest report for bondareko/bitcore-lib:
https://snyk.io/test/github/bondareko/bitcore-lib

Author: snyk-bot

package.json

@@ -85,7 +85,7 @@
     "buffer-compare": "=1.0.0",
     "elliptic": "=3.0.3",
     "inherits": "=2.0.1",
-    "lodash": "=3.10.1"
+    "lodash": "=4.17.5"
   },
   "devDependencies": {
     "bitcore-build": "bitpay/bitcore-build",