Update schema version for 1.2.x

[thekaveman]

Explain pull request

This is a fix for the schema version bug identified in #669 targeting the forthcoming 1.2.0 release of MDS. The issue left open the possibility of a separate hotfix for the 1.1.x line (e.g. a 1.1.1 release); this PR does not address the hotfix and a separate PR would be needed. Please follow-up on the issue if you are interested.

Is this a breaking change

• No, not breaking

Impacted Spec

• policy
• provider

Additional context

I also snuck in a fix to a timestamp minimum value in the policy.json schema, a follow-on from the work done and already merged in #648. I missed that when I did the review!

Important reminder for schema changes:

1. First edit the relevant templates in the schema/ directory at the root of this repository
2. Then run the generate_schemas.py script, also found in that directory, to regenerate the schemas from the templates
3. Review the regenerated schema files and commit changes as necessary

[schnuerle]

Thanks for the fix. I'll contact you to see about doing a patch for 1.1 as well.