build(deps): bump google.golang.org/api from 0.123.0 to 0.126.0

Bumps [google.golang.org/api](https://github.com/googleapis/google-api-go-client) from 0.123.0 to 0.126.0.
- [Release notes](https://github.com/googleapis/google-api-go-client/releases)
- [Changelog](https://github.com/googleapis/google-api-go-client/blob/main/CHANGES.md)
- [Commits](https://github.com/googleapis/google-api-go-client/compare/v0.123.0...v0.126.0)

---
updated-dependencies:
- dependency-name: google.golang.org/api
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/google/s2a-go/internal/handshaker/service/service.go

@@ -21,8 +21,9 @@ package service
 
 import (
 	"context"
-	"flag"
 	"net"
+	"os"
+	"strings"
 	"sync"
 	"time"
 
@@ -32,10 +33,10 @@ import (
 	"google.golang.org/grpc/grpclog"
 )
 
+// An environment variable, if true, opportunistically use AppEngine-specific dialer to call S2A.
+const enableAppEngineDialerEnv = "S2A_ENABLE_APP_ENGINE_DIALER"
+
 var (
-	// enableAppEngineDialer indicates whether an AppEngine-specific dial option
-	// should be used.
-	enableAppEngineDialer bool
 	// appEngineDialerHook is an AppEngine-specific dial option that is set
 	// during init time. If nil, then the application is not running on Google
 	// AppEngine.
@@ -50,7 +51,6 @@ var (
 )
 
 func init() {
-	flag.BoolVar(&enableAppEngineDialer, "s2a_enable_appengine_dialer", false, "If true, opportunistically use AppEngine-specific dialer to call S2A.")
 	if !appengine.IsAppEngine() && !appengine.IsDevAppServer() {
 		return
 	}
@@ -75,7 +75,7 @@ func Dial(handshakerServiceAddress string) (*grpc.ClientConn, error) {
 		grpcOpts := []grpc.DialOption{
 			grpc.WithInsecure(),
 		}
-		if enableAppEngineDialer && appEngineDialerHook != nil {
+		if enableAppEngineDialer() && appEngineDialerHook != nil {
 			if grpclog.V(1) {
 				grpclog.Info("Using AppEngine-specific dialer to talk to S2A.")
 			}
@@ -90,3 +90,10 @@ func Dial(handshakerServiceAddress string) (*grpc.ClientConn, error) {
 	}
 	return hsConn, nil
 }
+
+func enableAppEngineDialer() bool {
+	if strings.ToLower(os.Getenv(enableAppEngineDialerEnv)) == "true" {
+		return true
+	}
+	return false
+}