fix(deps): update dependency express to v4.20.0 [security]

Author: renovate[bot]

package.json

@@ -39,7 +39,7 @@
     "bulma": "0.7.4",
     "compression": "1.7.4",
     "cross-env": "5.2.0",
-    "express": "4.16.4",
+    "express": "4.20.0",
     "intersection-observer-polyfill": "0.1.0",
     "localforage": "1.7.3",
     "lru-cache": "5.1.1",