Use inner-page-no-masthead style

In response to build error:
     Build Warning: Layout 'news' requested in news/_posts/2017-07-26-release-notes-2.12.3.md does not exist.

Author: retronym

news/_posts/2017-07-26-release-notes-2.12.3.md

@@ -1,5 +1,5 @@
 ---
-layout: news
+layout: inner-page-no-masthead
 post-type: announcement
 permalink: /news/2.12.3
 title: "Scala 2.12.3 is now available!"