Update dependency loopback-component-explorer to v5.4.0 (#919)

Author: renovate[bot]

appengine/loopback/package.json

@@ -18,7 +18,7 @@
     "cors": "2.8.5",
     "helmet": "3.15.0",
     "loopback-boot": "2.27.1",
-    "loopback-component-explorer": "5.3.0",
+    "loopback-component-explorer": "5.4.0",
     "serve-favicon": "2.5.0",
     "strong-error-handler": "2.3.2",
     "loopback-datasource-juggler": "3.28.0",