Read version from pyproject.toml

[0jc1]

This addresses #103

The function get_version_from_toml() only works for 3.10+. Prior versions do not have a built-in toml reader.

[stevepiercy]

Thanks for this PR! Sorry for the long delay to respond.

The concept is nice, and I have a few suggestions. Would you please take care? Thank you!

[0jc1]

Good suggestions, i applied all of them.

it might be necessary to specify tomli as a dependency in pyproject.toml like this:

[project]
dependencies = [
    'tomli ; python_version < "3.11"'
]