Fix deprecated vsprintf usage in Engine logging 2nd edition (#1978)

Replace deprecated vsprintf with vsnprintf to eliminate compiler warning
and prevent potential buffer overflow. Updated to latest commit.

Tested in game and it seemed to log actions just fine. I just basically
added a buffer size by using the current vsnprintf lib instead.

src/strategy/Engine.cpp

@@ -606,7 +606,7 @@ void Engine::LogAction(char const* format, ...)
 
     va_list ap;
     va_start(ap, format);
-    vsprintf(buf, format, ap);
+    vsnprintf(buf, sizeof(buf), format, ap);
     va_end(ap);
 
     lastAction += "|";