Because github actions don't allow overriding ENTRYPOINT we need a custom repanda image where we can use environmental variables and arguments to specify such things as log level.
DEFAULT_LOG_LEVEL
passed to redpanda startup args, useful values are 'trace' or 'info'
example1: build docker run -t --rm --hostname redpanda_ci_image --name=redpanda_ci_image --env CREATE_TOPICS=foo,bar,baz ${IMG}
example2: build docker run -t --rm --hostname redpanda_ci_image --name=redpanda_ci_image --env CREATE_TOPICS=foo,bar:1,baz:3 ${IMG}