Update dependency pg-promise to v11 [SECURITY]

Author: renovate[bot]

package.json

@@ -67,7 +67,7 @@
     "lru-cache": "^4.1.3",
     "merge-graphql-schemas": "^1.5.3",
     "morgan": "^1.9.0",
-    "pg-promise": "^8.4.5",
+    "pg-promise": "^11.0.0",
     "prettier": "^1.14.0",
     "ramda": "0.25.0",
     "shortid": "^2.2.12"