tests: fixing dependencies that brake tests in go.1.15.15

- retry_interceptor_test causes:
clientv3/naming/grpc.go:25:2: module google.golang.org/grpc@latest found (v1.46.0),
but does not contain package google.golang.org/grpc/naming
#12124

clientv3/retry_interceptor_test.go

@@ -1,8 +1,25 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Based on github.com/grpc-ecosystem/go-grpc-middleware/retry, but modified to support the more
+// fine grained error checking required by write-at-most-once retry semantics of etcd.
+
 package clientv3
 
 import (
-	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
-	"go.etcd.io/etcd/client/v3/credentials"
+	"go.etcd.io/etcd/clientv3/credentials"
+	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
 	grpccredentials "google.golang.org/grpc/credentials"
 	"testing"
 )