update pyproject.toml to handle Python 3.10 and Apple arm64

[grlee77]

Description

adds cases for Apple M1 processors and Python 3.10

drop cases related to Python 3.6 which we no longer support

Checklist

• Docstrings for all functions
• Gallery example in ./doc/examples (new features only)
• Benchmark in ./benchmarks, if your changes aren't covered by an
  existing benchmark
• Unit tests
• Clean style in the spirit of PEP8
• Descriptive commit messages (see below)

For reviewers

• Check that the PR title is short, concise, and will make sense 1 year
  later.
• Check that new functions are imported in corresponding __init__.py.
• Check that new features, API changes, and deprecations are mentioned in
  doc/release/release_dev.rst.

[grlee77]

@hmaarrfk, any chance you (or others!) are available to give this a quick look?

[hmaarrfk]

Looks good thanks!