Incorrect events cache invalidation on Issue.updated_at

[Martin Krizek]

DefaultWrapper.get_events() uses DefaultWrapper.load_update_fetch_rest() to load events and timeline from cache files. For determining whether the cache is up to date it uses date from Issue.updated_at. The problem is that it appears that Issue.updated_at does not reflect update time of events like cross-reference. So if only updates to the issue are events like cross-reference after the issue is updated, labels like has_pr and has_issue are not added because cache is not invalidated and events are not loaded from GH.

This needs more investigation.

Example: ansible/ansible#66943

[Martin Krizek]

Fixed in #1616