Style: format code by gofumpt (#761)

common/protocol/tls/cert/cert_test.go

@@ -73,6 +73,7 @@ func printJSON(certificate *Certificate) {
 	os.Stdout.Write(content)
 	os.Stdout.WriteString("\n")
 }
+
 func printFile(certificate *Certificate, name string) error {
 	certPEM, keyPEM := certificate.ToPEM()
 	return task.Run(context.Background(), func() error {
@@ -81,6 +82,7 @@ func printFile(certificate *Certificate, name string) error {
 		return writeFile(keyPEM, name+"_key.pem")
 	})
 }
+
 func writeFile(content []byte, name string) error {
 	f, err := os.Create(name)
 	if err != nil {