Update cython requirement from ==0.* to ==3.*

[dependabot]

Updates the requirements on cython to permit the latest version.

Changelog

Sourced from cython's changelog.

3.0.0 unified release notes

Cython 3.0.0 has been a very large effort that cleaned up many old warts, introduced many new features, and introduces a couple of intentional behaviour changes, even though the goal remained to stay compatible as much as possible with Cython 0.29.x. For details, see the migration guide_.

.. _migration guide: https://cython.readthedocs.io/en/latest/src/userguide/migrating_to_cy30.html

As the development was spread out over several years, a lot of things have happened in the meantime. Many crucial bugfixes and some features were backported to 0.29.x and are not strictly speaking "new" in Cython 3.0.0.

Major themes in 3.0.0

Compatibility with Python

Since Cython 3.0.0 started development, CPython 3.8-3.11 were released. All these are supported in Cython, including experimental support for the in-development CPython 3.12. On the other end of the spectrum, support for Python 2.6 was dropped.

Cython interacts very closely with the C-API of Python, which is where most of the adaptation work happens. Independently, Cython strives to be able to parse newer Python constructs for use with its pure python_ mode, which has been a focus. In short, this allows to compile a wider range of Python code into optimized C code.

.. _pure python: https://cython.readthedocs.io/en/latest/src/tutorial/pure.html

Implemented PEPs ^^^^^^^^^^^^^^^^

• PEP-3131_: Supporting Non-ASCII Identifiers (Github issue :issue:2601)
• PEP-479_: generator_stop (enabled by default for language_level=3) (Github issue :issue:2580)
• PEP-487_: Simpler customisation of class creation (Github issue :issue:2781)
• PEP-563_: Postponed Evaluation of Annotations (Github issue :issue:3285)
• PEP-570_: Positional-Only Parameters (Github issue :issue:2915)
• PEP-572_: Assignment Expressions (a.k.a. the walrus operator :=) (Github issue :issue:2636)
• PEP-590_: Vectorcall protocol (Github issue :issue:2263)
• PEP-614_: Relaxing Grammar Restrictions On Decorators (Github issue :issue:4570)

Typing support in the sense of PEP-484_ (Github issues :issue:3949, :issue:4243) and PEP-560_ (Github issues :issue:2753, :issue:3537, :issue:3764) was also improved.

.. _PEP-3131: https://www.python.org/dev/peps/pep-3131 .. _PEP-479: https://www.python.org/dev/peps/pep-0479

... (truncated)

Commits

• 2f3a781 Prepare release of Cython 3.0.0.
• ac4f0bb Update changelog.
• 039ef7c In Py2, the extension type might get cleaned up before the objects at system ...
• 8edd90a Prepare second release candidate 3.0.0rc2.
• 7efee97 Update changelog.
• c0a3556 Test including "complex.h" in MSVC (#5527)
• 36a3702 Write the version to stderr as before, but only if stderr is actually capture...
• 8169009 Update changelog and version.
• 864e563 Support hex constants in enums (GH-5525)
• 0c6141a Document @​cython.with_gil (GH-5522)
• Additional commits viewable in compare view

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[dependabot]

Looks like cython is no longer updatable, so this is no longer needed.