Migrate development extras to dependency groups

[kurtmckee]

Note

These changes are being introduced because extras appear in lock files. When Dependabot opens security vulnerability PRs, the dev, docs, and tests extras also appear in the diff. In addition, having test dependencies as extras can affect dependency version resolution.

This PR will also eliminate the unnecessary extras appearing on the PyPI page:

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This introduces the following changes:

• The dev extra is moved to a dependency group.

• The tests extra is moved to a dependency group.

• The docs extra is moved to a dependency group.

• tox.ini has been updated to use the dependency groups.

• main.yml has been updated to install the dev dependency group.

• The Read the Docs config is updated to install the docs dependency group.

  This follows the how-to documentation published by Read the Docs. https://docs.readthedocs.com/platform/latest/build-customization.html#install-dependencies-from-dependency-groups

In addition, when tox was run, the lint environment failed because pyupgrade doesn't support Python 3.9.
Therefore, one additional change was made:

• The lint tox environment's basepython is updated to Python 3.10.

[Copilot]

Pull request overview

This PR migrates contributor-focused dependencies (dev, docs, tests) from project.optional-dependencies (extras) to PEP 735 dependency groups, and updates automation to install those groups to reduce lockfile noise and avoid exposing contributor extras on PyPI.

Changes:

• Add [dependency-groups] in pyproject.toml and remove dev/docs/tests from project.optional-dependencies.
• Update tox.ini envs to install tests/docs/dev via dependency_groups (and bump lint to Python 3.10).
• Update CI and RTD config to install dependency groups instead of extras.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pyproject.toml	Defines dev/docs/tests dependency groups and removes corresponding extras.
tox.ini	Switches tox env dependency installation from extras to dependency groups; sets lint to Python 3.10.
.github/workflows/main.yml	Updates dev install step to use --group dev.
.readthedocs.yaml	Changes RTD install behavior to install docs group (and crypto extra).
CHANGELOG.rst	Notes migration from extras to dependency groups under Unreleased.

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