Drop 1.6 announcement

Author: cwickham

_quarto.yml

@@ -23,10 +23,6 @@ website:
   repo-actions: [edit, issue]
   page-navigation: true
   bread-crumbs: true
-  announcement: 
-     content: "🎉 Quarto 1.6 released! [Download](/docs/download/) | [Read More](/docs/blog/posts/2024-11-25-1.6-release)"
-     position: below-navbar
-     dismissable: true
   search:
     show-item-context: true
     type: overlay