fix: .snyk, package.json & package-lock.json to reduce vulnerabilities

The following vulnerabilities are fixed with a Snyk patch:
- https://snyk.io/vuln/SNYK-JS-LODASH-450202

.snyk

+# Snyk (https://snyk.io) policy file, patches or ignores known vulnerabilities.
+version: v1.13.5
+ignore: {}
+# patches apply the minimum changes required to fix a vulnerability
+patch:
+  SNYK-JS-LODASH-450202:
+    - lodash:
+        patched: '2019-07-03T22:35:04.771Z'
+    - winston > async > lodash:
+        patched: '2019-07-03T22:35:04.771Z'

package.json

@@ -13,7 +13,9 @@
     "lint-fix": "eslint . --fix",
     "start": "node cli.js",
     "test": "npm run lint && jasmine",
-    "cover": "istanbul cover --root lib --print detail jasmine"
+    "cover": "istanbul cover --root lib --print detail jasmine",
+    "snyk-protect": "snyk protect",
+    "prepare": "npm run snyk-protect"
   },
   "dependencies": {
     "ajv": "^6.5.4",
@@ -29,7 +31,8 @@
     "prettier": "^1.17.0",
     "readdirp": "^2.1.0",
     "valid-url": "1.0.9",
-    "winston": "^3.1.0"
+    "winston": "^3.1.0",
+    "snyk": "^1.189.0"
   },
   "devDependencies": {
     "@semantic-release/changelog": "^3.0.2",
@@ -68,5 +71,6 @@
     "ghooks": {
       "pre-commit": "npx lint-staged"
     }
-  }
+  },
+  "snyk": true
 }