Add milestones to epics
I think this is a question much related to #6222 (closed) "difference between epics and milestones". As I understand the great explanation by @gweaver there, epics describe a high level view of general project planning, whereas milestones are a less abstract organization of the next steps ahead, towards a specific goal.
So for example an epic might be a large customer project, and milestones could be specific deliverables.
In this view, it would very much make sense to assign some milestones to an epic, and the milestones' issues would then inherit that epic as their parent.
Release notes
- Epics can now have milestones, each issue of the milestone automatically has the epic as parent.
Problem to solve
Working with epics and milestones is cumbersome because two properties have to be edited at the same time, and the epic is redundant since everything belonging to one milestone has the same epic anyway.