Fix post header to use processed image (#118)

Author: robinsonzimmermann

src/app/features/post/post.component.html

@@ -28,7 +28,7 @@ <h2>{{ post.excerpt }}</h2>
         </div>
       </div>
       <div class="post__header-image">
-        <img [src]="post | postUrl: post.teaser" alt="" />
+        <img [src]="post | postUrl : post.displayTeaser?.lg" alt="" />
       </div>
     </header>
     <div class="post__content">