May 21 (Reuters) - Gold edged lower on Friday, as optimism around a swift economic recovery lifted appeal for riskier assets, although a weaker dollar and growing inflationary pressure limited losses and kept bullion on track for a third straight weekly rise. * Risk sentiment in wider financial markets remained upbeat after strong U.S. jobs data lifted hopes around a quick economic recovery. * Britain's economy will grow much faster than expected this year as a fast-moving coronavirus vaccine programme allows businesses to re-open and lifts confidence, a Reuters poll found.