fix update.sh and env.example

Author: michelroegl-brunner

.env.example

@@ -26,4 +26,4 @@ AUTH_PASSWORD_HASH=
 AUTH_ENABLED=false
 AUTH_SETUP_COMPLETED=false
 JWT_SECRET=
-DATABASE_URL="/opt/ProxmoxVE-Local/data/settings.db"
+DATABASE_URL="file:/opt/ProxmoxVE-Local/data/settings.db"