Drop support for Ember < 3.4

This commit is, I’ll confess, controversial. However, ember-apollo-client
only supports Ember >= 3.4 and it makes our lives *much* easier to follow
suit.

The real source of the 3.4 minimum is ember-native-class-polyfill which
ember-apollo-client now requires Ember < 3.6.

As per [the ember-apollo-client 2.0.0 release notes][1]:

> If you are using Ember versions 3.4 or 3.5 you must add
> ember-native-class-polyfill to your application.

[1]: https://github.com/ember-graphql/ember-apollo-client/releases/tag/v2.0.0

Author: Jamie White

.travis.yml

@@ -44,17 +44,22 @@ jobs:
         - yarn test
         - cat coverage/lcov.info | node_modules/coveralls/bin/coveralls.js
 
+    - stage: "Additional Tests"
+      name: "Floating Dependencies"
+      install:
+        - yarn install --no-lockfile --non-interactive
+      script:
+        - yarn test
+
     # we recommend new addons test the current and previous LTS
     # as well as latest stable release (bonus points to beta/canary)
-    - stage: "Additional Tests"
-      env: EMBER_TRY_SCENARIO=ember-lts-2.16
-    - env: EMBER_TRY_SCENARIO=ember-lts-2.18
-    - env: EMBER_TRY_SCENARIO=ember-lts-3.4
-    - env: EMBER_TRY_SCENARIO=ember-lts-3.8
+    - env: EMBER_TRY_SCENARIO=ember-lts-3.12
+    - env: EMBER_TRY_SCENARIO=ember-lts-3.16
     - env: EMBER_TRY_SCENARIO=ember-release
     - env: EMBER_TRY_SCENARIO=ember-beta
     - env: EMBER_TRY_SCENARIO=ember-canary
     - env: EMBER_TRY_SCENARIO=ember-default-with-jquery
+    - env: EMBER_TRY_SCENARIO=ember-classic
 
 script:
   - node_modules/.bin/ember try:one $EMBER_TRY_SCENARIO

config/ember-try.js

@@ -7,45 +7,18 @@ module.exports = async function() {
     useYarn: true,
     scenarios: [
       {
-        name: 'ember-lts-2.16',
-        env: {
-          EMBER_OPTIONAL_FEATURES: JSON.stringify({ 'jquery-integration': true })
-        },
-        npm: {
-          devDependencies: {
-            '@ember/jquery': '^0.5.1',
-            'ember-apollo-client': '2.0.0-beta.1',
-            'ember-source': '~2.16.0'
-          }
-        }
-      },
-      {
-        name: 'ember-lts-2.18',
-        env: {
-          EMBER_OPTIONAL_FEATURES: JSON.stringify({ 'jquery-integration': true })
-        },
-        npm: {
-          devDependencies: {
-            '@ember/jquery': '^0.5.1',
-            'ember-apollo-client': '2.0.0-beta.1',
-            'ember-source': '~2.18.0'
-          }
-        }
-      },
-      {
-        name: 'ember-lts-3.4',
+        name: 'ember-lts-3.12',
         npm: {
           devDependencies: {
-            'ember-apollo-client': '2.0.0-beta.1',
-            'ember-source': '~3.4.0'
+            'ember-source': '~3.12.0'
           }
         }
       },
       {
-        name: 'ember-lts-3.8',
+        name: 'ember-lts-3.16',
         npm: {
           devDependencies: {
-            'ember-source': '~3.8.0'
+            'ember-source': '~3.16.0'
           }
         }
       },
@@ -73,31 +46,41 @@ module.exports = async function() {
           }
         }
       },
+      // The default `.travis.yml` runs this scenario via `yarn test`,
+      // not via `ember try`. It's still included here so that running
+      // `ember try:each` manually or from a customized CI config will run it
+      // along with all the other scenarios.
       {
         name: 'ember-default',
+        npm: {
+          devDependencies: {}
+        }
+      },
+      {
+        name: 'ember-default-with-jquery',
         env: {
           EMBER_OPTIONAL_FEATURES: JSON.stringify({
             'jquery-integration': true
           })
         },
         npm: {
           devDependencies: {
-            '@ember/jquery': '^0.5.1',
-            'ember-apollo-client': '2.0.0-beta.1'
+            '@ember/jquery': '^0.5.1'
           }
         }
       },
       {
-        name: 'ember-default-with-jquery',
+        name: 'ember-classic',
         env: {
           EMBER_OPTIONAL_FEATURES: JSON.stringify({
-            'jquery-integration': true
+            'application-template-wrapper': true,
+            'default-async-observers': false,
+            'template-only-glimmer-components': false
           })
         },
         npm: {
-          devDependencies: {
-            '@ember/jquery': '^0.5.1',
-            'ember-apollo-client': '2.0.0-beta.1'
+          ember: {
+            edition: 'classic'
           }
         }
       }