My colleague Ruben explores the wonderful world of GitHub actions.
You can write workflows in YAML, which makes them easy to write and read. In the beta version of GitHub Actions you had to use Ocaml, which was quite hard to comprehend, and there was almost no documentation. If you were a bit frightened by the beta version, like me, then rest assured: the YAML version is easier to use, and the documentation is well written.
Source: Freek Van der Herten