fix maintenance policy header

Author: tylerjroach

src/pages/reference/maintenance-policy/index.mdx

@@ -3,7 +3,13 @@ export const meta = {
   description: 'The maintenance policy for all Amplify Client Libraries.'
 };
 
-# AWS Amplify Client Library Maintenance Policy
+export function getStaticProps() {
+  return {
+    props: {
+      meta
+    }
+  };
+}
 
 ## Overview