Provide an option to group by Release

[rahul-ramadas]

The "Group By" list in work items queries does not include Release. It would be nice if it did; perhaps even make it customizable enough to allow it to be grouped by any field.

[supermem613]

Unfortunately, "Release" is not a standard field but rather a custom one (see https://docs.microsoft.com/en-us/azure/devops/boards/work-items/guidance/work-item-field?view=azure-devops). The "standard" field used for version is "Iteration Path", which we show as "Iteration" in the group by.

At this point we don't have plans to add extensibility hooks / settings for custom fields. Keeping as part of the overall backlog.