I run Drone CI for a longer period now with Docker. Because I decided to switch for multiple reasons from Docker to Podman, this setup had to be changed a bit.
After installing Podman, it could be that you will not find docker images. For that, you should add the following lines to /etc/containers/registries.conf:
Drone CI uses a mapping of the Docker Socket. This mapping has to be changed so that Drone CI thinks that Podman is our Docker instance.