📚 Doc: add LoggerFunc and Logger to middleware logger

docs/middleware/logger.md

@@ -108,6 +108,8 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | TimeZone         | `string`                   | TimeZone can be specified, such as "UTC" and "America/New_York" and "Asia/Chongqing", etc                                        | `"Local"`                                                             |
 | TimeInterval     | `time.Duration`            | TimeInterval is the delay before the timestamp is updated.                                                                       | `500 * time.Millisecond`                                              |
 | Output           | `io.Writer`                | Output is a writer where logs are written.                                                                                       | `os.Stdout`                                                           |
+| LoggerFunc           | `func(c fiber.Ctx, data *Data, cfg Config) error`  | You can use custom loggers with Fiber by using this field. This field is really useful if you're using Zerolog, Zap, Logrus, apex/log etc. If you don't define anything for this field, it'll use default logger of Fiber.  | `see default_logger.go defaultLoggerInstance`                                                           |
+| Logger           | `fiberlog.AllLogger`  |   |                                                           |
 | DisableColors    | `bool`                     | DisableColors defines if the logs output should be colorized.                                                                    | `false`                                                               |
 | enableColors     | `bool`                     | Internal field for enabling colors in the log output. (This is not a user-configurable field)                                    | -                                                                     |
 | enableLatency    | `bool`                     | Internal field for enabling latency measurement in logs. (This is not a user-configurable field)                                 | -                                                                     |