Replace RawExtrinsicMetadata `id` attribute with `target`.
The old attribute was deprecated in swh.model 0.7.2
Test Plan
tox throws fewer deprecation warnings
Migrated from D4361 (view on Phabricator)
Staging instance, all changes can be removed at any time
The old attribute was deprecated in swh.model 0.7.2
tox throws fewer deprecation warnings
Migrated from D4361 (view on Phabricator)