I don't know but reading between the lines: soon.

This article happened because Waymo wanted it to happen.

Waymo has a very strict NDA which is why outside of Google press releases we haven't heard a word about how this early rider program works.

Google explicitly allowed Bloomberg reporter to interview few people who used Waymo car.

The only reason for Waymo to allow this publicity is because they are gearing up for a public, unrestricted release.

They publicly stated they plan to launch this year (https://www.cnet.com/roadshow/news/waymo-self-driving-car-se...)

I'm doubting the merits of a rumour I heard it would be August. 'Sometime this year' is what Waymo has been saying since March. In November last year they said 'In a few months'.

In the article it talks about how the app has been displaying trip prices for the test users (even though they don't pay). No dates given but that's a positive step.