Replace RawExtrinsicMetadata `id` attribute with `target`.
The old attribute was deprecated in swh.model 0.7.2
Test Plan
tox -e py3 -- -W error:RawExtrinsicMetadata:DeprecationWarning
Migrated from D4365 (view on Phabricator)
The old attribute was deprecated in swh.model 0.7.2
tox -e py3 -- -W error:RawExtrinsicMetadata:DeprecationWarning
Migrated from D4365 (view on Phabricator)