Drop support for ember < 4.12 (#1026)

Author: mkszepp

.github/workflows/ci.yml

@@ -113,9 +113,6 @@ jobs:
       fail-fast: false
       matrix:
         try-scenario:
-          - ember-lts-3.28
-          - ember-lts-4.4
-          - ember-lts-4.8
           - ember-lts-4.12
           - ember-lts-5.4
           - ember-lts-5.8

ember-basic-dropdown/README.md

@@ -26,7 +26,7 @@ It is intended to be a building block for more complex components but is perfect
 ### Compatibility
 
 - Embroider or ember-auto-import v2
-- Ember.js v3.28 or above
+- Ember.js v4.12 or above
 
 ### Installation
 

test-app/config/ember-try.js

@@ -7,46 +7,6 @@ module.exports = async function () {
   return {
     usePnpm: true,
     scenarios: [
-      {
-        name: 'ember-lts-3.28',
-        npm: {
-          devDependencies: {
-            '@glimmer/component': '^1.1.2',
-            '@ember/test-helpers': '^2.9.4',
-            'ember-cli': '~4.12.2',
-            'ember-load-initializers': '^2.1.2',
-            'ember-qunit': '^6.0.0',
-            'ember-resolver': '^8.0.0',
-            'ember-source': '~3.28.0',
-            'ember-truth-helpers': '^4.0.3',
-          },
-        },
-      },
-      {
-        name: 'ember-lts-4.4',
-        npm: {
-          devDependencies: {
-            '@glimmer/component': '^1.1.2',
-            '@ember/test-helpers': '5.1.0',
-            '@ember/test-waiters': '^3.1.0',
-            'ember-load-initializers': '^2.1.2',
-            'ember-resolver': '^8.0.0',
-            'ember-source': '~4.4.0',
-            'ember-truth-helpers': '^4.0.3',
-          },
-        },
-      },
-      {
-        name: 'ember-lts-4.8',
-        npm: {
-          devDependencies: {
-            '@glimmer/component': '^1.1.2',
-            'ember-load-initializers': '^2.1.2',
-            'ember-resolver': '^11.0.0',
-            'ember-source': '~4.8.0',
-          },
-        },
-      },
       {
         name: 'ember-lts-4.12',
         npm: {