By Ross Kerber BOSTON (Reuters) - After scoring a landmark win at Exxon Mobil Corp over climate concerns last year, activist investor Engine No. 1 is broadening its sights to press companies on diversity and workforce issues in 2022. Michael O'Leary, who oversees investment stewardship at the San Francisco-based firm, said it will want more explanation from portfolio companies this spring about their obligations to employees as stakeholders, their workforce demographics, and other matters.