Use a released version of jsonschema

[gadomski]

I think this is causing us to pick up an alpha version of jsonschema in downstreams, which is causing hard-to-track down breakages.

IMO, released versions of packages should depend on released versions of other packages when at all possible.

If possible, it'd be great to get a release (BUGFIX or otherwise) of stac-check after this is merged, so downstreams can pick up the dependency fix.

Context

• jsonschema put out an alpha release of 4.18 that considered empty fragments invalid: Draft 7 schema with an $id containing an empty fragment produces resolution errors for subresources python-jsonschema/jsonschema#1064 (comment)
• Some of the STAC schemas (e.g. https://schemas.stacspec.org/v1.0.0/collection-spec/json-schema/collection.json) have empty fragments
• Because stac-check depends on a beta jsonschema version, I think this was turning on pre-release installs for any resolution of jsonschema dependencies: https://pip.pypa.io/en/stable/cli/pip_install/#pre-release-versions
• This broke validation checks in various CIs (e.g. https://github.com/stac-utils/stactools/actions/runs/4490766359/jobs/7900073955?pr=405) because if stac-check was in the enviornment, jsonschema could/would be installed as the alpha release

[pjhartzell]

I'm OK with this change, but will defer to @jonhealy1 for approval.