Bump copyright year

Author: roji

docfx.json

@@ -84,7 +84,7 @@
     "xrefService": [ "https://xref.docs.microsoft.com/query?uid={uid}" ],
     "globalMetadata": {
       "_appTitle": "Npgsql Documentation",
-      "_appFooter": "© Copyright 2025 The Npgsql Development Team",
+      "_appFooter": "© Copyright 2026 The Npgsql Development Team",
       "_appLogoPath": "img/logo.svg",
       "_enableSearch": true,
       "_gitContribute": {