The German Federal Cartel Office has approved plans by carmaker Volkswagen to buy a stake in US electric car manufacturer Rivian, it said on Monday. The joint venture planned by the two companies and VW’s minority stake in Rivian have been given the all-clear, the authority said. “There is no cause for concern here due to the project, nor are there any other serious competition problems to be feared,” said the cartel office president, Andreas Mundt, according to the press release. The cooperation announced in June involves software, control computers and network architecture. New VW cars are t…