Bump attrs from 20.3.0 to 21.1.0

[dependabot]

Bumps attrs from 20.3.0 to 21.1.0.

Changelog

Sourced from attrs's changelog.

21.1.0 (2021-05-06)

Deprecations ^^^^^^^^^^^^

• The long-awaited, much-talked-about, little-delivered import attrs is finally upon us!

  Since the NG APIs have now been proclaimed stable, the next release of attrs will allow you to actually import attrs. We're taking this opportunity to replace some defaults in our APIs that made sense in 2015, but don't in 2021.

  So please, if you have any pet peeves about defaults in attrs's APIs, now is the time to air your grievances in #487! We're not gonna get such a chance for a second time, without breaking our backward-compatibility guarantees, or long deprecation cycles. Therefore, speak now or forever hold you peace! [#487](https://github.com/python-attrs/attrs/issues/487) <https://github.com/python-attrs/attrs/issues/487>_

• The cmp argument to attr.s() and attr.ib() has been undeprecated It will continue to be supported as syntactic sugar to set eq and order in one go.

  I'm terribly sorry for the hassle around this argument! The reason we're bringing it back is it's usefulness regarding customization of equality/ordering.

  The cmp attribute and argument on attr.Attribute remains deprecated and will be removed later this year. [#773](https://github.com/python-attrs/attrs/issues/773) <https://github.com/python-attrs/attrs/issues/773>_

Changes ^^^^^^^

• It's now possible to customize the behavior of eq and order by passing in a callable. [#435](https://github.com/python-attrs/attrs/issues/435) <https://github.com/python-attrs/attrs/issues/435>, [#627](https://github.com/python-attrs/attrs/issues/627) <https://github.com/python-attrs/attrs/issues/627>

• The instant favorite next-generation APIs <https://www.attrs.org/en/stable/api.html#next-gen>_ are not provisional anymore!

  They are also officially supported by Mypy as of their 0.800 release <https://mypy-lang.blogspot.com/2021/01/mypy-0800-released.html>_.

  We hope the next release will already contain an (additional) importable package called attrs. [#668](https://github.com/python-attrs/attrs/issues/668) <https://github.com/python-attrs/attrs/issues/668>, [#786](https://github.com/python-attrs/attrs/issues/786) <https://github.com/python-attrs/attrs/issues/786>

• If an attribute defines a converter, the type of its parameter is used as type annotation for its corresponding __init__ parameter.

  If an attr.converters.pipe is used, the first one's is used. [#710](https://github.com/python-attrs/attrs/issues/710) <https://github.com/python-attrs/attrs/issues/710>_

• Fixed the creation of an extra slot for an attr.ib when the parent class already has a slot with the same name. [#718](https://github.com/python-attrs/attrs/issues/718) <https://github.com/python-attrs/attrs/issues/718>_

• __attrs__init__() will now be injected if init=False, or if auto_detect=True and a user-defined __init__() exists.

  This enables users to do "pre-init" work in their __init__() (such as super().__init__()).

  __init__() can then delegate constructor argument processing to self.__attrs_init__(*args, **kwargs). [#731](https://github.com/python-attrs/attrs/issues/731) <https://github.com/python-attrs/attrs/issues/731>_

... (truncated)

Commits

• b22195e Prepare 21.1.0
• c5ae43f Pin towncrier
• 503164f Fix changelog template for towncrier 21.3.0
• fbed032 Revert last change, the string is consistent w/ total_ordering
• 2f395f1 Make docstring consistent with the rest
• f41db43 Unpin pyright & minor docs polish
• 16f7a0d Make #796 newsfragment more timeless
• eb2df7f Add announcement about import attrs
• c6f6bb3 Revert "Pin 3.10 to last alpha (#802)"
• 7e372c5 Implement pyright support via dataclass_transforms (#796)
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)