chore: admin-api default version v2 (#1558) (#1559)

diff --git a/pkg/config/config.go b/pkg/config/config.go
index c5718e4..9828353 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -143,7 +143,7 @@
 			EnableGatewayAPI:    false,
 		},
 		APISIX: APISIXConfig{
-			AdminAPIVersion:    "v3",
+			AdminAPIVersion:    "v2",
 			DefaultClusterName: "default",
 		},
 	}