Upwork (UPWK) appears an attractive pick given a noticeable improvement in the company's earnings outlook. The stock has been a strong performer lately, and the momentum might continue with analysts still raising their earnings estimates for the company.The rising trend in estimate revisions, which is a result of growing analyst optimism on the earnings prospects of this online freelance marketplace operator, should get reflected in its stock price. After all, empirical research shows a strong correlation b ...