Bump ember-concurrency

Author: kategengler

package.json

@@ -68,7 +68,7 @@
     "ember-cli-showdown": "^9.0.1",
     "ember-cli-terser": "^4.0.2",
     "ember-composable-helpers": "^5.0.0",
-    "ember-concurrency": "^4.0.3",
+    "ember-concurrency": "^4.0.6",
     "ember-data": "~4.6.0",
     "ember-data-fastboot": "https://github.com/mainmatter/ember-data-fastboot#update-babel",
     "ember-decorators": "^6.1.1",