Make the mqtt submodule logging tags lower case

Author: AndriiFilippov

lib/mqtt_outbox.c

@@ -5,7 +5,7 @@
 #include "esp_log.h"
 
 #ifndef CONFIG_MQTT_CUSTOM_OUTBOX
-static const char *TAG = "OUTBOX";
+static const char *TAG = "outbox";
 
 typedef struct outbox_item {
     char *buffer;

lib/platform_esp32_idf.c

@@ -8,7 +8,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 
-static const char *TAG = "PLATFORM";
+static const char *TAG = "platform";
 
 #define MAX_ID_STRING (32)
 

mqtt_client.c

@@ -32,7 +32,7 @@ _Static_assert(sizeof(uint64_t) == sizeof(outbox_tick_t), "mqtt-client tick type
 _Static_assert(MQTT_EVENT_ANY == ESP_EVENT_ANY_ID, "mqtt-client event enum does not match the global EVENT_ANY_ID");
 #endif
 
-static const char *TAG = "MQTT_CLIENT";
+static const char *TAG = "mqtt_client";
 
 #ifdef MQTT_SUPPORTED_FEATURE_EVENT_LOOP
 /**