Sequoia Capital China, widely viewed as a bellwether for Chinese tech investment, is set to lay off as much as 20 per cent of investment staff as a slowdown in the country’s tech sector saps appetite for risk, said two people with knowledge of the matter.The Chinese arm of Silicon Valley venture capitalist Sequoia Capital is looking to cut the number of venture investment professionals from about 70, the people said. Two other people said the cut would be at least 10 per cent.Sequoia China told…