There is no specific trigger action for whenever SharePoint news is posted. This article explains how you could work around this by using a trigger condition expression.
My name is Dennis. I am Dutch and I live and work in the UK as an IT consultant. Currently I work a lot with SharePoint online, Microsoft Teams and all the other products of the Office 365 platform. I also like my share of Dynamics 365 and Azure. I try to blog about everything I come across in my daily job. All the content in my blogs are my personal views and experiences.