The behaviour for an action-specific resource change.
To implement one, simply implement the behaviour.
c:init/1 is defined automatically
use Ash.Resource.Change, but can be implemented if you want to validate/transform any
options passed to the module.
The main function is
c:change/3. It takes the changeset, any options that were provided
when this change was configured on a resource, and the context, which currently only has