Multiple feeds to update the same content

Imported content can now be tracked by multiple feeds. This way Feeds can properly see if content by each feed has changed. Previously, when you used more than one feed to update the same content, Feeds would see all content updated by feed 1 as changed when importing these with feed 2. This caused that a lot of items that were not changed got reimported.

There's also a change in how to get a value from the feed item. You now need a Feed entity to get the right one:

Before

/** @var \Drupal\feeds\Plugin\Field\FieldType\FeedsItem $feeds_item */
$feeds_item = $entity->get('feeds_item')->first();

After

/** @var \Drupal\feeds\FeedInterface $feed */
/** @var \Drupal\feeds\Plugin\Field\FieldType\FeedsItem $feeds_item */
$feeds_item = $entity->get('feeds_item')->getItemByFeed($feed);