Add a field for the version of the standard the data is published to

[duncandewhurst]

Related issues
Add links to related issues here. Use keywords if you want an issue to be automatically closed when the PR is merged.

• Closes Add a field for the version of the standard the data is published to #91

Description
If the changes in the PR are not sufficiently explained by the related issues and commit messages, add a description here

Also updates examples/csv/nodes.csv to reflect the change in 2e6d36c

Merge checklist

• If there are changes to network-schema.json, network-package-schema.json, reference/publication_formats/json.md, reference/publication_formats/geojson.md or guidance/publication.md#how-to-publish-large-networks, update the relevant manually authored examples:
  • examples/json/:
    • network-package.json
    • api-response.json
    • multiple-networks.json
    • network-embedded.json
    • network-separate-endpoints.json
    • network-separate-files.json
    • nodes-endpoint.json
    • spans-endpoint.json
  • examples/geojson/:
    • api-response.geojson
    • multiple-networks.geojson
• Run ./manage.py pre-commit to update derivative schema files, reference documentation and examples
• If there are changes to examples/geojson/nodes.geojson or examples/geojson/spans.geojson, check and update the data use examples:
  • examples/leaflet/leaflet.ipynb
  • examples/qgis/geojson.qgs
• Update the changelog (style guide)

---

@odscjames assigning to you for a review as I think this might be helpful to get merged before @lgs85 returns from leave.

[duncandewhurst]

Noting that this PR may need updating based on Open-Telecoms-Data/lib-cove-ofds#13 (comment)

[duncandewhurst]

@odscjames I've made the update discussed in Open-Telecoms-Data/lib-cove-ofds#13. Prior to draft 2020-12, tuple validation was handled differently so this schema will only behave as intended with validators that support draft 2020-12. jsonschema supports 2020-12 so hopefully that is not an issue for CoVE.

In order to permit only one 'describedby' link in links, I've added a pattern validation to Link.rel to permit any value except 'describedby'. However, I've run into the same issue as described in #145, whereby the regex does not behave as expected when I test it with https://www.jsonschemavalidator.net/. Any ideas?

[duncandewhurst]

@odscjames I've fixed the regex issue (thanks to @lgs85) so this is ready for you to review again. In particular, please check that you're happy with the use of JSON Schema 2020-12 described in my previous comment. Thanks!

[duncandewhurst]

I had to resolve a merge conflict in the changelog so another review is required.