(Reuters) – Russians have rushed to buy Chinese yuan to diversify their holdings away from U.S. dollars and euros, the state bank Otkritie said, as the finance ministry aims to re-start foreign exchange interventions using ‘friendly’ nations’ currencies. Demand for the yuan has increased eightfold since May 20 when the central bank lifted the restrictions on forex-buying that it introduced to limit the impact of western sanctions on the financial sector, Otkritie, under sanctions itself, said in a note. At the same time, purchases of the British pound and Swiss francs by Russians have increase…