codemeta: Add compatibility with PyLD >= 2.0.0.

indexer build in failure [1]

since that change [2] got deployed upstream.

This commit fixes it.

• [1] https://jenkins.softwareheritage.org/job/DCIDX/job/tests/945

• [2] https://github.com/digitalbazaar/pyld/commit/46d2ca38c7b5c63696336eefdb543daecda622f3

Test Plan

Fixes the Jenkins build

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Migrated from D3049 (view on Phabricator)