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

Author: renovate[bot]

package.json

@@ -26,7 +26,7 @@
     "isomorphic-fetch": "3.0.0",
     "jest": "27.5.1",
     "npm-run-all": "4.1.5",
-    "start-server-and-test": "1.14.0",
+    "start-server-and-test": "1.15.4",
     "wait-on": "6.0.1"
   }
 }