fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-QS-14724253

package.json

@@ -14,7 +14,7 @@
     "axios": "^0.15.3",
     "connect-history-api-fallback": "^1.3.0",
     "debounce": "^1.0.0",
-    "express": "^4.16.1",
+    "express": "^4.22.0",
     "numeral": "^2.0.4",
     "vue": "^2.1.0",
     "vue-axios": "^1.2.2",