Fix unique key prop for blog

src/templates/blog.js

@@ -9,9 +9,8 @@ class Blog extends Component {
     return (
       <div className="container mx-auto p-4 w-full md:flex md:flex-wrap items-stretch w-full">
         {data.allWordpressPost.edges.map(({ node }) => (
-          <div className="md:w-1/2 p-2">
+          <div key={node.id} className="md:w-1/2 p-2">
             <Card
-              key={node.id}
               url={`blog/${node.slug}`}
               title={node.title}
               date={node.date}