Prefect

This release adds status displays for work queue health to the UI and support for waiting for upstream tasks before starting a subflow!

It also includes:

- Scheduler performance improvements
- Documentation for our [versioning scheme](https://docs.prefect.io/contributing/versioning/)
- Three new collections: GitLab, Alerts, and Fivetran!

See the full [release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-266) for more details.

This release includes bug fixes and enhancements to the core library. The highlights are:

- Support for manual flow run retries
- Improved server performance when retrying flow runs with many tasks
- Status checks in work queues
- Support for Python 3.11

See the [release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-265) for details.

This release includes bug fixes and enhancements to the core library, but the highlights are in our collections. There's a new [infrastructure block for running flows in containers on Azure](https://prefecthq.github.io/prefect-azure/container_instance/), a new [key-value store collection](https://madkinsz.github.io/prefect-kv/), and the [ECS infrastructure block](https://prefecthq.github.io/prefect-aws/ecs/) has been designated as ready for production.

See the [release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-264) for details.

By the way, if you haven't checked out [2.6](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-260) yet, you should now! We launched first-class configuration of results in 2.6.0 and every release since includes additional improvements to result handling.

This release fixes a bug in [2.6.2](https://github.com/PrefectHQ/prefect/releases/tag/2.6.2) where `Task.with_options` could fail due to a null value for the new `cache_result_in_memory` setting.

This release includes some major enhancements, including support for compound recurrence rule schedules and private GitHub repositories. There are also fixes and enhancements for the new results feature; notably, we now support reducing memory consumption by optionally always retrieving results from storage.

As always, the highlights above are a small subset of the changes. See the [release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-262) for everything else!

This release patches a bug where flow and task return values of `{}` or `[]` could be incorrectly coerced to `None`.