feat: Support process scoped variables

[tleed5]

[SC-66829]
Based on #562

Result

• Updated go-octopusdeploy version to include the changes that allow for process scope variable matching (see chore: Support process scoped variable scope matching OctopusDeploy/go-octopusdeploy#230)
• Add process to variable scope schema to allow it to be used in terraform.

Example

resource "octopusdeploy_variable" "test_variable" {
  owner_id  = "Projects-21"
  type      = "String"
  name      = "Test Process Scope"
  value     = "Scopey"
  scope {
    processes = ["Runbooks-1"]
  }
}

fixes #361

[zentron]

Looks reasonable. If we can add (or update an existing) test to include the usage of this parameter would be nice.

[tleed5]

Tenant scoped variables are already been tested here so it didn't seem necessary to test them again

[tleed5]

I figure we can just assert that the correct amount of variables are created, anything else would be covered by the fact the variable resources are created correctly.

[zentron]

Apart from maybe a quick tweak to the test to validate that the scope exists as expected, even just explicitly checking some known value for each differently scoped variable then feel free to merge.
🙇 Thanks for pushing this one forward