teaser_columns_block: center title fixes #141

Author: philli-m

apps/academy/templates/academy/blocks/teaser_columns_block.html

@@ -1,5 +1,5 @@
 <section>
-    <h2 class="academy__sans-serif text--upper">{{ value.headline }}</h2>
+    <h2 class="academy__sans-serif text--upper text-center">{{ value.headline }}</h2>
     <div class="item-list">
         <div class="row justify-content-center list-unstyled">
         {% for teaser in value.teasers %}