Actually test against 4.8 in CI

Author: gitKrystan

.github/workflows/ci-build.yml

@@ -47,7 +47,7 @@ jobs:
         ember-try-scenario:
           - ember-lts-3.28
           - ember-lts-4.4
-          - ember-lts-4.4
+          - ember-lts-4.8
           - ember-release
           - ember-beta
           - ember-canary