Dask-awkward

Major update
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**Refactoring of the necessary columns optimization (148)**: this was a very large PR that touched a lot of the code base. The dask-awkward configuration was changed to go along with the new optimization that is based on running the task graph on awkward typetracer arrays.

New
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- Add dak.values_astype (166)
- Scalar support getitem and getattr via Delayed (168)

Other
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- Some pre-commit/CI updates

New
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- Register with `dask.sizeof` (142)
- Use length zero arrays of metadata for metadata tracking when necessary (143, 162)
- Configuration parameter `awkward.raise-failed-meta` (default is `False`) controls whether an exception is raised if the the metadata of a new collection cannot be determined automatically. (162)
- Support integer dtype arrays as the `where` parameter of `getitem` calls (158)
- More awkward namespace operations supported (146)

Fixes
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- Remove need for explicit computation in `dak.with_name` (150)
- Upstream `UnknownScalar` removal (152)
- Relax partition checking for dak.concatenate (161)
- Remove xfail from a distributed test (149)

Other
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- License as nested text (157)
- Some pre-commit and CI updates

New features
- Add `dak.concatenate` with `axis>=0` support. (125)
- Add `dak.unzip` support (136)
- Add `dak.where` support (133)
- Add `dak.with_field` support (137)

Fixes
- Remove `flatten_records` keyword argument from reducers (remove deprecation warning from upstream `awkward`) (139)
- Fix getitem optimization such that only starting fields can be discovered (131)

Other
- More documentation (132)
- Some pre-commit updates

This is the first official release of dask-awkward!

Please find the documentation at https://dask-awkward.readthedocs.io/