feat: drive the resource class via a job parameter and default to small

[ralbertazzi]

Similar to this PR for the path-filtering/filter job, it would be great to customize the resource class of the continue job.

According to the official documentation, if you do not specify a size, resource_class will be set automatically. In my case, the continuation job runs in the large class and it costs a ton of credit. Therefore, we need to add a resource_class parameter to allow selection of the size of the resource_class for continuation jobs.

[Fernando-Abreu]

@ralbertazzi would you mind rebasing so the conflict are resolved

[ralbertazzi]

There you go ;) Would be great to see this merged

[ralbertazzi]

Any chance to see this merged after 5 months and 2 approvals? It's a really tiny change that would make customers happier..