belt_inventory_helper.h: if (level >= _countof(beltGradeByLevelTable)) [-Wsign-compare] Warning

In file included from char_item.cpp:47:
belt_inventory_helper.h: In static member function 'static CBeltInventoryHelper::TGradeUnit CBeltInventoryHelper::GetBeltGradeByRefineLevel(int)':
belt_inventory_helper.h:28:13: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   28 |   if (level >= _countof(beltGradeByLevelTable))

    static TGradeUnit GetBeltGradeByRefineLevel(int level)

    static TGradeUnit GetBeltGradeByRefineLevel(unsigned int level)