Add 1.4 announcement (#992)

Author: cwickham

_quarto.yml

@@ -50,7 +50,10 @@ website:
         aria-label: Quarto GitHub
       - icon: rss
         href: https://quarto.org/docs/blog/index.xml
-        aria-label: Quarto Blog RSS        
+        aria-label: Quarto Blog RSS
+  announcement: 
+    content: "🎉 Quarto 1.4 released! [Download](/docs/download/), [Read More](/docs/blog/posts/2024-01-24-1.4-release/)"
+    position: below-navbar
   navbar:
     background: light
     logo: quarto.png

theme.scss

@@ -31,3 +31,15 @@ $text-muted: #6a737b;
   margin-bottom: 0.5rem;
 }
 
+#quarto-announcement {
+  padding: 1em;
+  font-size: 1em;
+  font-weight: bold;
+  color: $white;
+  background-color: #447099; 
+}
+
+#quarto-announcement a {
+  color: $white;
+}
+