Fix build on Arduino ESP32 v3.0.0 and IDF 5.1.1

[blackhack]

This fixes compilation on the latest Git version of the Arduino ESP32 core due to API changes in IDF 5.1.

Of course, these changes make ESPAsyncWebServer incompatible with prior Arduino core versions.

[rel1ct]

In WebAuthentication.cpp -> #ifdef ESP32 + #include "esp_idf_version.h"

if(ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)){
mbedtls_md5_starts(&_ctx);
mbedtls_md5_update(&_ctx, data, len);
mbedtls_md5_finish(&_ctx, _buf);
}else{
mbedtls_md5_starts_ret(&_ctx);
mbedtls_md5_update_ret(&_ctx, data, len);
mbedtls_md5_finish_ret(&_ctx, _buf);
}

In AsyncWebSocket.cpp
change
#ifdef ESP8266
#include "mbedtls/sha1.h"
#elif ESP32
#include "mbedtls/sha1.h"
#include "rom/ets_sys.h"
#include "esp_idf_version.h"
#else
#include <Hash.h>
#endif

if(ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)){
mbedtls_sha1_starts_ret(&ctx);
mbedtls_sha1_update_ret(&ctx, (const unsigned char*)key.c_str(), key.length());
mbedtls_sha1_finish_ret(&ctx, hash);
}else{
mbedtls_sha1_starts(&ctx);
mbedtls_sha1_update(&ctx, (const unsigned char*)key.c_str(), key.length());
mbedtls_sha1_finish(&ctx, hash);
}

[vanThijs]

When I make this modification, I receive a warning that the "mbedtls_md5_starts()" function is depreciated and superseded by "mbedtls_md5_starts_ret()". Swapping the modified functions back to the original "..._ret()" versions doesn't break the compilability of the code.