Awkward

reikdas added a tool to check which GPU kernels have been implemented (565).

ianna implemented multi-JSON reading and nan/inf/-inf string substitution (568).

trickarcher added more loop-dependent GPU kernels (454).

jpivarski added the 'initial' argument to ak.min/ak/max (566), created a pass-through "awkward1" package (564), fixed up the documentation, and renamed the `master` branch as `main` (569).

First actual 1.0 version!

Also, fixed booleans in Numba (559), setting a virtual field with `__setitem__` (561), and renamed `awkward1` → `awkward` everywhere (563).

Another batch of [November bug-fixes](https://github.com/scikit-hep/awkward-1.0/projects/2):

nsmith- made mixin classes derived from a decorator pickleable (542).

ianna fixed a bug in sort/argsort (524) and concatenate (548).

reikdas added a script to clean up generated files (556).

jpivarski generalized `ak.where` to take a non-NumPy `condition` (544), implemented `__contains__` in and out of Numba (547), `np.array(ak.Array)` in Numba (550), removed the right-broadcast from `ak.with_field` (553), implemented `ak.to_regular` and `ak.from_regular` (551), updated the GitHub issue templates, and fixed a bug affecting Coffea (https://github.com/CoffeaTeam/coffea/issues/372, PR #558).

Mostly bug-fixes, but a few new functions:

* PR 495: reikdas added a test to ensure kernel signatures match specification, are in order
* PR 517: masked `__getitem__` on empty arrays
* PR 518: fixed `ak.to_pandas` with IndexedArrays and other nodes
* PR 519: `ak.local_index`
* PR 520: actually removed long-deprecated Pandas code
* PR 525: fixed the definition of `Form::getitem_field`
* PR 526: infinite recursion bug in Arrow translation
* PR 527: definition of "mergeable" with parameters (different `__doc__` is mergeable, different `__record__` is not)
* PR 535: `ak.zeros_like`, `ak.ones_like`, `ak.full_like`
* PR 536: enforce minimum pyarrow version (2.0.0)
* PR 537: fixed matrix multiplication (multiply many differently sized matrices with one ``!)
* PR 539: ianna implemented `ak.concatenate` for `axis > 0`!
* PR 540: performance issues in `__setitem__`

Calling ufuncs on any custom types (not just records) will raise errors unless a customization is defined for exactly that ufunc and type. Some custom types, like "categorical," need to handle arbitrary ufuncs, so I also added a "apply_ufunc" interface to define behaviors across the board. (513)

Added copy and deepcopy, both with the Python interface (`copy` module) and with the NumPy interface (`np.copy`). (514)

Fixed the cache-handling of version 0.4.2. (515)

Mutable `ak.Array.cache` has been replaced with immutable `ak.Array.caches`, which always contains all the VirtualArray caches in the whole layout; it no longer needs to be maintained by users.

This is an interface-breaking change (with deprecation warnings), and a new release is needed to bring uproot4 up to date with the change.