Update jsonargparse[signatures] requirement from <4.19.0,>=4.18.0 to >=4.18.0,<4.22.0 in /requirements

[dependabot]

Updates the requirements on jsonargparse[signatures] to permit the latest version.

Changelog

Sourced from jsonargparse[signatures]'s changelog.

v4.21.1 (2023-05-09)

Fixed ^^^^^

• AST resolver not working for dict used in a method when the dict is created using the curly braces syntax.
• Failure on multiple deep arguments linked on instantiation ([#275](https://github.com/omni-us/jsonargparse/issues/275) <https://github.com/omni-us/jsonargparse/issues/275>__).

v4.21.0 (2023-04-21)

Added ^^^^^

• Support for dataclasses nested in a type ([#243](https://github.com/omni-us/jsonargparse/issues/243) <https://github.com/omni-us/jsonargparse/issues/243>__).
• Support for pydantic models <https://docs.pydantic.dev/usage/models/>__ and attrs define <https://www.attrs.org/en/stable/examples.html>__ similar to dataclasses.
• Support for pydantic types <https://docs.pydantic.dev/usage/types/#pydantic-types>__.
• Backport type stubs in python<=3.9 to support PEP 585 <https://peps.python.org/pep-0585/>__ and 604 <https://peps.python.org/pep-0604/>__ syntax.

Fixed ^^^^^

• str parameter in subclass incorrectly parsed as dict with implicit null value ([#262](https://github.com/omni-us/jsonargparse/issues/262) <https://github.com/omni-us/jsonargparse/issues/262>__).
• Wrong error indentation for subclass in union (lightning#17254 <https://github.com/Lightning-AI/lightning/issues/17254>__).
• dataclass from pydantic not working ([#100](https://github.com/omni-us/jsonargparse/issues/100) comment <https://github.com/omni-us/jsonargparse/issues/100#issuecomment-1408413796>__).
• add_dataclass_arguments not forwarding sub_configs parameter.
• Failure to instantiate nested class group without arguments (lightning#17263 <https://github.com/Lightning-AI/lightning/issues/17263>__).

Changed ^^^^^^^

• Switched from setup.cfg to pyproject.toml for configuration.
• Removed build_sphinx from setup.py and documented how to build.
• Include enum members in error when invalid value is given (lightning#17247 <https://github.com/Lightning-AI/lightning/issues/17247>__).
• The signatures extras now installs the typing-extensions package on python<=3.9.
• CLI now when given a class without methods, the class instance is returned.

... (truncated)

Commits

• 0942fb9 Bump version: 4.21.0 → 4.21.1
• 677a0f9 [pre-commit.ci] auto fixes from pre-commit.com hooks
• 37e9cbf Refactored util tests using pytest.
• f3f74d1 adding black formatting (#279)
• 1c303a6 Fixed failure on multiple deep arguments linked on instantiation (#275).
• d7e6dde add Ruff as code check (#280)
• 8d57577 Refactored loaders_dumpers, namespace and optionals tests using pytest.
• 54bf840 Refactored formatters, jsonschema and jsonnet tests using pytest.
• 0805435 Refactored actions, argcomplete and cli tests using pytest.
• 9039750 Removed some unittest specific code.
• Additional commits viewable in compare view

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cc @Borda