[examples/openspending][xs]: center align footer and make file previews wider

examples/openspending/components/_shared/Footer.tsx

@@ -4,21 +4,18 @@ export default function Footer() {
   return (
     <footer>
       <div className="mx-auto max-w-7xl px-4 sm:px-6 lg:px-8 flex flex-col items-center justify-between md:flex-row">
-        <div className="flex gap-x-2 items-center">
+        <div className="flex gap-x-2 items-center mx-auto">
           <p className="mt-8 text-base text-slate-500 md:mt-0">Maintained by</p>
-          <a href="https://www.datopian.com/">
+          <a href="https://www.datopian.com/" target="_blank">
             <Image
               alt="Datopian logo"
               className="mb-2"
               src="/datopian-logotype.png"
-              width={160}
-              height={40}
+              width={120}
+              height={30}
             />
           </a>
         </div>
-        <p className="mt-6 text-base text-slate-500 md:mt-0">
-          Copyright © 2023 Datopian, LLC. All rights reserved.
-        </p>
       </div>
     </footer>
   );