Update grid layout for blog section

Author: JustinMissmahl

src/routes/blog.index.tsx

@@ -98,7 +98,7 @@ function BlogIndex() {
                 The latest news and blog posts from TanStack
               </p>
             </header>
-            <section className="grid grid-cols-1 md:grid-cols-2 2xl:grid-cols-3 gap-4">
+            <section className="grid grid-cols-1 xl:grid-cols-2 2xl:grid-cols-3 gap-4">
               {frontMatters.map(
                 ({ slug, title, published, excerpt, headerImage, authors }) => {
                   return (