fix(git): add vendor in .gitignore

vendor/google.golang.org/api/internal/conn_pool.go

@@ -1,30 +0,0 @@
-// Copyright 2020 Google LLC.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package internal
-
-import (
-	"google.golang.org/grpc"
-)
-
-// ConnPool is a pool of grpc.ClientConns.
-type ConnPool interface {
-	// Conn returns a ClientConn from the pool.
-	//
-	// Conns aren't returned to the pool.
-	Conn() *grpc.ClientConn
-
-	// Num returns the number of connections in the pool.
-	//
-	// It will always return the same value.
-	Num() int
-
-	// Close closes every ClientConn in the pool.
-	//
-	// The error returned by Close may be a single error or multiple errors.
-	Close() error
-
-	// ConnPool implements grpc.ClientConnInterface to enable it to be used directly with generated proto stubs.
-	grpc.ClientConnInterface
-}