add tender.sustainability and sustainabilityStrategies.csv

[odscjen]

Related issues
closes #400

Description

the sustainability extension has sustainability as an array of Sustainability objects. But as we're only bringing in Sustainability.strategies I don't think we need to make sustainability an array here, it can be a single instance which is what I've done

Merge checklist

• Log your changes

If there are changes to project-schema.json or project-package-schema.json:

• Update the examples:
  • docs/examples/example.json
  • docs/examples/blank.json
• Run ./manage.py pre-commit to update docs/_static/i8n.csv

If you added a new definition to the schema, run ./manage.py pre-commit.

If you added a new codelist:

• Add an entry to docs/reference/codelists.md

[duncandewhurst]

the sustainability extension has sustainability as an array of Sustainability objects. But as we're only bringing in Sustainability.strategies I don't think we need to make sustainability an array here, it can be a single instance which is what I've done

Generally, we've tried to align ContractingProcessSummary.Tender with the Tender definition in OCDS so I'm inclined to think that .sustainability should be an array, as in the extension. @jpmckinney what do you think?

[jpmckinney]

Let's keep it as an array as in OCDS for consistency and future-proofing.

[odscjen]

I've changed it to an array. I agree about the future proofing but I do think having an array of objects which themselves are made of a single array is potentially confusing.

[duncandewhurst]

Happy for you to request a review from James once my comments are resolved.

[odscjen]

The error is a result of no id field, the test needs changed as discussed #438 (comment)