Add 3.0.0 release notes to pkgdown site

_pkgdown.yml

@@ -11,20 +11,9 @@ template:
     in_header: |
       <script defer data-domain="withr.r-lib.org,all.tidyverse.org" src="https://plausible.io/js/plausible.js"></script>
 
-navbar:
-  type: default
-  left:
-  - icon: fa-home fa-lg
-    href: index.html
-  - text: Reference
-    href: reference/index.html
-  - text: Articles
-    href: articles/index.html
-  - text: News
-    menu:
-      - text: "Release notes"
-      - text: "Version 2.1.0"
-        href: "https://www.tidyverse.org/blog/2017/11/withr-2.1.0/"
-      - text: "------------------"
-      - text: "Change log"
-        href: news/index.html
+news:
+  releases:
+  - text: "Version 3.0.0"
+    href: https://www.tidyverse.org/blog/2024/01/withr-3-0-0/
+  - text: "Version 2.1.0"
+    href: https://www.tidyverse.org/blog/2017/11/withr-2.1.0/