fix whats new not showing latest changes (#2639)

Author: patricklx

app/routes/whats-new.js

@@ -45,7 +45,7 @@ export default class WhatsNewRoute extends TabRoute {
     let ref = version.indexOf('alpha') === -1 ? `v${version}` : 'main';
     let url = `https://raw.githubusercontent.com/emberjs/ember-inspector/${encodeURIComponent(
       ref,
-    )}/CHANGELOG.md`;
+    )}-ember-inspector/CHANGELOG.md`;
 
     return fetch(url)
       .then(checkStatus)

tests/acceptance/whats-new-test.js

@@ -7,7 +7,7 @@ import { setupTestAdapter } from '../test-adapter';
 function urlFor(ref) {
   return `https://raw.githubusercontent.com/emberjs/ember-inspector/${encodeURIComponent(
     ref,
-  )}/CHANGELOG.md`;
+  )}-ember-inspector/CHANGELOG.md`;
 }
 
 function generateContent(main = false) {