Regions to be an unordered TypeSet

[JanBerktold]

Closes #314

[fformica]

Hey, thanks for the contribution!

[JanBerktold]

My apologies @fformica - I thought this was a draft and wasn't done testing it.

Thanks for catching the array/Set mishap. My remaining concern is that this code path sets a []map[string]interface{} instead of a Set for `regions. I am not familiar enough with TF to know whether it magically translates those under the hood.

		regions := make([]map[string]interface{}, 0, len(r.Regions))
		for _, k := range keys {
		for name, region := range r.Regions {
			newRegion := make(map[string]interface{})
			region := r.Regions[k]
			newRegion["name"] = k
			newRegion["name"] = name
			newRegion["meta"] = region.Meta.StringMap()
			regions = append(regions, newRegion)
		}
		log.Printf("Setting regions %+v", regions)
		err := d.Set("regions", regions)
		if err != nil {
			return fmt.Errorf("[DEBUG] Error setting regions for: %s, error: %#v", r.Domain, err)
		}

[fformica]

Ah, sorry, we should have a new release soon so I hurried to get this in.
Anyway, it's ok, the slice is converted to a Set internally: https://github.com/hashicorp/terraform-plugin-sdk/blob/v2.24.1/helper/schema/field_writer_map.go#L297

[JanBerktold]

Awesome, ty! Thanks for getting this out quickly.