Upgrade to jsonschema 4.18.0

[jpmckinney]

Closes #112
Closes #130

As described in the documentation linked from #112 , the new version of jsonschema separates resolution from caching.

RefResolver had no handlers by default. lib-cove had copied these lines.

This also fixes add_is_codelist() being unreachable from one branch of the if-statement, a bug introduced in 011a2bd

The upgraded causes test_property_that_is_not_json_schema_doesnt_raise_exception to now raises an error. I'm not sure why this scenario shouldn't raise an error.

jsonschema 4.18 drops support for Python 3.6 and 3.7.

Includes #118

[jpmckinney]

Test failure is from BODS being included, again.

[jpmckinney]

I made #128 and #129 now as easier-to-merge alternatives, which give lib-cove-ocds the flexibility it needs to (1) use the latest jsonschema and (2) not see deprecation warnings.

[odscjames]

I made #128 and #129 now as easier-to-merge alternatives, which give lib-cove-ocds the flexibility it needs to (1) use the latest jsonschema and (2) not see deprecation warnings.

As those 2 are now merged, is this important to do?

[jpmckinney]

jsonschema will continue to release new versions, so it makes sense to keep up with its development.

Also, this prevents a scenario where you’ll be tempted to set a maximum version on jsonschema when some future version causes an error.

[jpmckinney]

Changes are quite small when you ignore whitespace: https://github.com/OpenDataServices/lib-cove/pull/123/files?w=1

The main change is the minimum version.

[odscjames]

This PR removes

Allow SchemaJsonMixin classes to define a validator method, that accepts lib-cove's JSON Schema draft 4 validator class and its format checker, and returns a validator instance. #128

That is on main but is not released yet - replaces it with specifying a "registry" value instead. Is this ok?

[jpmckinney]

I would like validator to be preserved as a method. In lib-cove-ocds, I wrap it in an lru_cache, which has a big impact when running the validator millions of times.

I don't think this PR removes validator. It just branched from main before validator was extracted to a method.

[jpmckinney]

@odscjames I fixed the merge conflicts, in case that helps.

[jpmckinney]

@odscjames I've added a new block to cove-oc4ids to display additional_closed_codelist_values and I have a branch ready for lib-cove-oc4ids where tests pass under the new version of lib-cove.

So, please don't let oc4ids or ocds integration tests be a blocker – I'll take responsibility for those.

[jpmckinney]

This PR's diff is easier to read with whitespace ignored: https://github.com/OpenDataServices/lib-cove/pull/123/files?w=1

[jpmckinney]

Done in #142