add bracket format (#15)

Reviewed-on: #15
Co-authored-by: andrey <andrey@4devs.io>
Co-committed-by: andrey <andrey@4devs.io>

writer_example_test.go

@@ -32,6 +32,6 @@ func ExampleFormatWithBracket() {
 	serviceLogger := logger.With(log.WithName("service_name"))
 	serviceLogger.Err(ctx, "error message")
 	// Output:
-	// 2038-01-19T06:14:07+03:00 [info] writer_example_test.go:30 "imfo message" num=42
+	// 2038-01-19T03:14:07Z [info] writer_example_test.go:30 "imfo message" num=42
-	// 2038-01-19T06:14:07+03:00 [error][service_name] writer_example_test.go:33 "error message"
+	// 2038-01-19T03:14:07Z [error][service_name] writer_example_test.go:33 "error message"
 }