I write them myself. When I'm ready to publish a post, I set that timestamp to the current time and deploy (I also have an isPublished boolean that controls whether it's seen in the list).
It's manual, but I'm also not sure how it could be more convenient =) no matter what I need to set the date somewhere, and I may as well keep it in the same place as the article. I don't have to do any other "work" to publish.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.