fix: package.json & .snyk to reduce vulnerabilities (#6)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:qs:20170213


The following vulnerabilities are fixed with a Snyk patch:
- https://snyk.io/vuln/npm:request:20160119

Latest report for d2s/koodiklinikka.fi-api:
https://snyk.io/test/github/d2s/koodiklinikka.fi-api

package.json

@@ -5,7 +5,9 @@
   "main": "index.js",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
-    "start": "node index.js"
+    "start": "node index.js",
+    "snyk-protect": "snyk protect",
+    "prepublish": "npm run snyk-protect"
   },
   "repository": {
     "type": "git",
@@ -32,7 +34,9 @@
     "newrelic": "^1.18.0",
     "node-twitter": "0.5.2",
     "stripe": "^4.23.1",
-    "superagent": "^0.21.0",
-    "validator": "^3.27.0"
-  }
+    "superagent": "^2.0.0",
+    "validator": "^3.27.0",
+    "snyk": "^1.38.1"
+  },
+  "snyk": true
 }