fix Arduino Client API, again

Espressif reverted the changes done to 3.1.0 in 3.1.1, see espressif/arduino-esp32#10776

so assuming going forward this API will be kept, make this an exception for 3.1.0

Author: mhaberler

src/PicoMQTT/config.h

@@ -27,7 +27,7 @@
 #endif
 
 #ifdef ESP32
-#if ESP_ARDUINO_VERSION >= ESP_ARDUINO_VERSION_VAL(3, 1, 0)
+#if ESP_ARDUINO_VERSION == ESP_ARDUINO_VERSION_VAL(3, 1, 0)
 #define PICOMQTT_EXTRA_CONNECT_METHODS
 #endif
 #endif