Update dependency ember-cli-babel to v8

Author: renovate[bot]

package.json

@@ -25,7 +25,7 @@
     "test": "ember test"
   },
   "dependencies": {
-    "ember-cli-babel": "^7.26.11"
+    "ember-cli-babel": "^8.0.0"
   },
   "devDependencies": {
     "@ember/optional-features": "2.1.0",