BRUSSELS (Reuters) -The European Commission is considering new joint debt issuance by the 27-nation bloc, two EU officials said, to cover Ukraine’s liquidity gap of 15 billion euros ($15.9 billion) over the next three months, though Germany is sceptical to the idea. A Commission proposal is to be published on May 18, one EU official said. The new joint EU borrowing, if agreed, could be based on the EU’s SURE scheme for financing unemployment benefits during the COVID-19 pandemic, officials said. This would mean that Ukraine would get very cheap loans from the bloc, and EU governments would nee…