fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:mime:20170907
- https://snyk.io/vuln/npm:debug:20170905
- https://snyk.io/vuln/npm:fresh:20170908
- https://snyk.io/vuln/npm:ms:20170412
- https://snyk.io/vuln/npm:qs:20170213

Latest report for labshare/services-cache:package.json:
https://snyk.io/test/github/labshare/services-cache?targetFile=package.json

package.json

@@ -14,7 +14,7 @@
   },
   "license": "MIT",
   "dependencies": {
-    "express": "4.14.0",
+    "express": "4.16.0",
     "lodash": "4.16.6",
     "q": "1.4.1",
     "redis": "2.6.3"