update headers

Author: avoonix

vercel.json

@@ -1,6 +1,6 @@
 {
   "redirects": [
-    { "source": "/", "destination": "https://material-e621.avoonix.com/", "statusCode": 301 }
+    { "source": "/", "destination": "https://material-e621.avoonix.com/", "statusCode": 301, permanent: true }
   ],
   "rewrites": [{ "source": "/old", "destination": "/index.html" }],
   "headers": [
@@ -21,6 +21,15 @@
           "value": "public, max-age=7776000"
         }
       ]
+    },
+    {
+      "source": "/(.*)",
+      "headers": [
+        {
+          "key": "Link",
+          "value": "<https://material-e621.avoonix.com/$1>; rel=\"canonical\""
+        }
+      ]
     }
   ]
 }