By Andrew Gould The Miami Marlins acquired third baseman Luke Williams from the San Francisco Giants in exchange for prospect Hayden Cantrelle. Williams went 3-for-12 with no walks in eight games with the Giants earlier this season before getting demoted. The 25-year-old fared much better in Triple-A, batting .378/.415/.486 with four stolen bases in 41 plate appearances. Miami announced the move on Thursday morning. Williams’ brightest moment arguably came for the U.S. national team. In four Summer Olympics qualifying games, he went 8-for-18 with six runs and RBI apiece. That stellar performan…