Update dependency open to v7.4.0

Author: renovate-bot

package-lock.json

@@ -29,7 +29,7 @@
   },
   "homepage": "https://github.com/mountaindude/node-red-contrib-open#readme",
   "dependencies": {
-    "open": "7.3.1"
+    "open": "7.4.0"
   },
   "devDependencies": {
     "jshint": "2.12.0"