Update dependency start-server-and-test to v1.15.4

Author: renovate[bot]

package.json

@@ -24,7 +24,7 @@
   "devDependencies": {
     "cypress": "3.4.1",
     "serve": "9.6.0",
-    "start-server-and-test": "1.9.1",
+    "start-server-and-test": "1.15.4",
     "@bahmutov/print-env": "1.2.0"
   }
 }