Drop support for Python 3.6 and jsonschema 3

[jpmckinney]

This along with #128 is an easier-to-merge alternative to #123. It will give lib-cove-ocds the flexibility it needs to (1) use the latest jsonschema and (2) not see deprecation warnings.

[odscjames]

Python 3.6 (and 3.7) support dropped and merged in #132

[odscjames]

Can you comment on the reasons for dropping JSONSchema 3 (beyond v3 hasn't been released since 2019)? Unfortunately it looks like it's pinned in 360 so we'll need to dig more into this one. https://github.com/ThreeSixtyGiving/dataquality/blame/42fc01837490083c852c99eec66020e854cd30db/setup.py#L18

[jpmckinney]

It becomes difficult to support both major versions of jsonschema.

Maybe try unpinning in 360?

Only consequence of merging is 360 effectively pins lib-cove until jsonschema is unpinned.

[michaelwood]

For reference this is the commit in 360Giving from a recent PR ThreeSixtyGiving/dataquality@0627357

I'm not very familiar with libcove, but 360Giving's cove could always pin to a compatible version of lib-cove for a time? The only request is that an upgrade path is possible.

[jpmckinney]

I think that incompatibility was fixed by cf97ed8

As I suggested, try unpinning - it’ll probably Just Work.

[odscjames]

Dropped in #133