jsonschema 4.10.0 is breaking asdf

[WilliamJamieson]

The release of jsonschema 4.10.0 has broken asdf

• https://github.com/asdf-format/asdf/runs/7860422378?check_suite_focus=true shows that asdf is now broken.
• Pin jsonschema below 4.10.0 #1171 demonstrates that this is due to jsonschema 4.10.0.

[WilliamJamieson]

There seams to be at least two errors:

1. This Depreciation warning: https://github.com/asdf-format/asdf/runs/7860409541?check_suite_focus=true#step:8:29720
2. This _id_of get error: https://github.com/asdf-format/asdf/runs/7860422378?check_suite_focus=true#step:9:28059

[WilliamJamieson]

Per this comment: python-jsonschema/jsonschema#981 (comment), it appears that our subclass of the jsonschema validator appears to not actually be supported. They appear to be working on a solution to this issue, which is being tracked python-jsonschema/jsonschema#982.

Thus we need to start looking into alternative ways to handle the extension of the validator which ASDFValidator provides.

[WilliamJamieson]

This was fixed by PR #1203