Remove offending include.

SFE-Brudnerd · SFE-Brudnerd · commit 213c7c01f549 · 2025-03-26T12:57:46.000-06:00
diff --git a/src/sfTkArdUART.h b/src/sfTkArdUART.h
@@ -13,7 +13,6 @@
 
 #pragma once
 
-#include <cstddef>
 #include <memory>
 
 #include <Arduino.h>
