Middleware move permanently fix (#810)

Author: strofimo

.changeset/hot-socks-beg.md

@@ -0,0 +1,5 @@
+---
+'@cloudflare/next-on-pages': patch
+---
+
+Middleware move permanently fix

packages/next-on-pages/templates/_worker.js/routes-matcher.ts

@@ -215,6 +215,12 @@ export class RoutesMatcher {
 			// to continue and did not rewrite/redirect the URL.
 			this.body = resp.body;
 			this.status = resp.status;
+		} else if (
+			resp.headers.has('location') &&
+			resp.status >= 300 &&
+			resp.status < 400
+		) {
+			this.status = resp.status;
 		}
 
 		applyHeaders(this.headers.normal, resp.headers);