User Activity based Expiration Policy for Office 365 groups is now generally available!

The actions that will renew a group, based on SharePoint activity, are: View, Edit, Download, Move, Share, and Upload Files.

The ability to auto-renew a Group (and therefore the SharePoint site) based on view, download, move, or share is inconsistent with the options in Office 365 retention labels (and records retention generally): 'date created', 'date last modified', or the date the label was applied. A disposition review *may* result in the extension of a retention policy, but the review itself doesn't automatically affect retention. 

Records generally (including those not in Office 365) may be viewed, downloaded, moved, or shared, for as long as it is subject to a retention policy, after which they may be deleted (subject to a disposition review). These actions do not alter the original record. Extending retention (which is effectively what auto-renew does) based on these events (not actions) doesn't make sense as it could result in permanent auto-renewals. 

Regardless of the above, it will not be possible to create a Group expiration policy if you don't have an Azure AD Premium licence.