While we cannot confirm if the screenshot is legit or not, it shows the improved Dragonflight UI and the Evoker spell icons on the action bars. The screenshot was taken in Valdrakken the new capital of the expansion. The minimap also displays the “!” quest indicator.
It appears the Evoker’s secondary resource is similar to Chi.
In the bottom right of the screen is a big red arrow that points to what appears to be a new fifth bag slot. If the image is fake, it is a high quality effort one.