Greta Thunberg is to become an ambassador for a Swedish charity foundation that grants wishes to children with serious illnesses. The 19-year-old Swedish climate activist has been involved with the foundation My Special Day for some time, but is now taking the next step and becoming an official ambassador, the organization said on Wednesday. Thunberg said she was honoured to be given the role in a video released by the foundation. “It means a lot to me because I think it’s important to shine a light on the struggle that many children and young people with illnesses silently fight every day,” s…