releaser: turn off upload to mirror by default (bazel-contrib#3677)

Most rules_go maintainers do not have direct access to Bazel team's
GSC bucket to upload this mirror. Let's disable it by default for
eventually removal.

Mirroring should be done by filing a requests in Bazel.git's Github
issues.

go/tools/releaser/file.go

@@ -286,16 +286,8 @@ func sha256SumFile(name string) (string, error) {
 // copyFileToMirror uploads a file to the GCS bucket backing mirror.bazel.build.
 // gsutil must be installed, and the user must be authenticated with
 // 'gcloud auth login' and be allowed to write files to the bucket.
+//
+// Deprecated: To mirror, please file a request to Bazel's Github Issue
 func copyFileToMirror(ctx context.Context, path, fileName string) (err error) {
-	dest := "gs://bazel-mirror/" + path
-	defer func() {
-		if err != nil {
-			err = fmt.Errorf("copying file %s to %s: %w", fileName, dest, err)
-		}
-	}()
-
-	// This function shells out to gsutil instead of using
-	// cloud.google.com/go/storage because that package has a million
-	// dependencies.
-	return runForError(ctx, ".", "gsutil", "cp", "-n", fileName, dest)
+	return nil
 }

go/tools/releaser/prepare.go

@@ -73,7 +73,7 @@ func runPrepare(ctx context.Context, stderr io.Writer, args []string) error {
 	var githubToken githubTokenFlag
 	var uploadToMirror bool
 	flags.Var(&githubToken, "githubtoken", "GitHub personal access token or path to a file containing it")
-	flags.BoolVar(&uploadToMirror, "mirror", true, "whether to upload dependency archives to mirror.bazel.build")
+	flags.BoolVar(&uploadToMirror, "mirror", false, "whether to upload dependency archives to mirror.bazel.build")
 	flags.StringVar(&rnotesPath, "rnotes", "", "Name of file containing release notes in Markdown")
 	flags.StringVar(&version, "version", "", "Version to release")
 	if err := flags.Parse(args); err != nil {

go/tools/releaser/upgradedep.go

@@ -130,7 +130,7 @@ func runUpgradeDep(ctx context.Context, stderr io.Writer, args []string) error {
 	if err != nil {
 		return err
 	}
-	for _, tool := range []string{"diff", "gazelle", "gsutil", "patch"} {
+	for _, tool := range []string{"diff", "gazelle", "patch"} {
 		if _, err := exec.LookPath(tool); err != nil {
 			return fmt.Errorf("%s must be installed in PATH", tool)
 		}