Ask HN: Should I blog on Medium for my open-source project, or self-host? 10 years ago
If its truly for just announcements, then evaluate several options and pick the simplest for you. Always remember that chances are very high that over time your goals for the blog will change and will outgrow your choice anyway.
If you are considering blogging for more than announcements and are new to authoring blogs, then I recommend "256 Bloghacks" by Yegor256 as a good starting point to know what to expect, and good ideas to consider. http://amzn.to/2i07fs2