Welcome back to Foreign Policy ’s Latin America Brief. The highlights this week: Mexico and the European Union update their trade agreement , a Brazilian drug gang travels to Ukraine to get smart on drones, and exiled Venezuelan opposition leader María Corina Machado plans her return. The Latest EU-Latin American Trade Pact Top European Union officials were in Mexico City last Friday for the first EU-Mexico summit in more than a decade. They left with something to show for it, signing an