Drop Python 3.10 support #604

Description

This is a placeholder issue to reference in source control. It is meant to capture all the changes that are needed when Python 3.10 support is no longer required.

Additional Details

• This issue could be completed to coincide with supporting Python 3.14, to stick with the "latest plus three previous releases" paradigm
• Consider using pyupgrade to automatically upgrade to 3.11+ syntax
  • Update the target-version key for the [tool.ruff] config in pyproject.toml
  • Use pyupgrade or ruff check --fix directly to make the changes to the files
• Update the requires-python key value in the [project] config in pyproject.toml
• Update the python_version key value in the [tool.refurb] config in pyproject.toml
• Ensure any packages that are only required for Python 3.10 are removed
• Update idioms used for Python 3.10 support only
  • Look for TODO: comments with this issue referenced
  • Look for more in "What's New in Python 3.11"
• Update the testing environments
  • in tox, GitHub workflows, etc.
  • Update the test_python_version test in tests/unit/test_package_metadata.py
• This might also be a good time to switch from black to ruff for formatting, if that change is desired

Acceptance Criteria

• Python 3.10 support is removed
• Documentation is updated