Add an explicit 5.4 LTS entry to CI

Author: mixonic

.github/workflows/ci.yml

@@ -66,6 +66,7 @@ jobs:
             ember-lts-4.4,
             ember-lts-4.8,
             ember-lts-4.12,
+            ember-lts-5.4,
             ember-release,
             ember-beta,
             ember-canary,

tests/dummy/config/ember-try.js

@@ -47,6 +47,14 @@ module.exports = async function () {
           },
         },
       },
+      {
+        name: 'ember-lts-5.4',
+        npm: {
+          devDependencies: {
+            'ember-source': '~5.4.0',
+          },
+        },
+      },
       {
         name: 'ember-release',
         npm: {