website/docs: fix PowerDNS Docker Hub repo name (#7134)

Update index.md

Change Docker Hub repository name : https://github.com/PowerDNS-Admin/PowerDNS-Admin/issues/1317

Signed-off-by: Baptistecottey <Baptistecottey@users.noreply.github.com>

website/integrations/services/powerdns-admin/index.md

@@ -63,7 +63,7 @@ You must mount the certificate selected in authentik as a file in the Docker con
 version: "3.3"
 services:
     powerdns-admin:
-        image: ngoduykhanh/powerdns-admin:latest
+        image: powerdnsadmin/pda-legacy:latest
         restart: always
         ports:
             - 80:80