By Milana Vinn Dec 17 - Goldman Sachs Group has hired Brian Cayne, a co-founder of boutique tech investment bank Qatalyst Partners, as a global co-head ​of its software investment banking group, according to people familiar with the matter. Cayne ‌is expected to start at the Wall Street giant in January, the people said, asking not to be ‌named to discuss confidential personnel matters. Based in San Francisco, Cayne will co-lead the software banking practice alongside existing co-heads Joe Porter in Lond ...