Update dependency @ember/string to v4

Author: renovate[bot]

ember-metrics-simple-analytics/package.json

@@ -33,7 +33,7 @@
   },
   "dependencies": {
     "@embroider/addon-shim": "1.9.0",
-    "@ember/string": "3.1.1",
+    "@ember/string": "4.0.1",
     "ember-metrics": "2.0.0-beta.2"
   },
   "devDependencies": {