Schema for the pgflow.steps table.
Represents a step within a flow with composite primary key (flow_slug, step_slug).
@type t() :: %PgFlow.Schema.Step{ __meta__: term(), deps: term(), deps_count: term(), flow: term(), flow_slug: term(), opt_base_delay: term(), opt_max_attempts: term(), opt_timeout: term(), step_slug: term(), step_states: term(), step_type: term() }