[BUGFIX] Updating ember-cli version to 3.9

cp-property-map codemod addresses deprecations introduced
in 3.9 hence updating the version

Author: rajasegar

manifest.json

@@ -84,7 +84,7 @@
   },
   "cp-property-map-codemod": {
     "versions": {
-      "ember-cli": "3.8.0-beta.1"
+      "ember-cli": "3.9.0-beta.1"
     },
     "projectOptions": ["app", "addon"],
     "nodeVersion": "6.0.0",