* chore: release v2.0.0a1 - resolve circular dependency (#489)

Make nac-test-pyats-common a direct dependency instead of optional
[adapters]/[all] extras. Users can now install with `pip install nac-test`
to get the complete runtime including PyATS adapters.

Changes:
- Bump version to 2.0.0a1
- Move nac-test-pyats-common>=0.3.0 to direct dependencies
- Remove [adapters] and [all] optional dependency groups
- Update CI workflow to remove --extra adapters
- Update author/maintainer metadata

Closes #489

* fix: restore [project.optional-dependencies] section header

The section header was accidentally removed when deleting the adapters/all
extras, causing the dev dependencies to become orphaned.

* update 2.0.0 Changelog entry

* fix: remove RESTinstance and setuptools pin from core dependencies

RESTinstance is no longer used by the test templates shipped with nac-test
and forces a setuptools<81 pin due to its pkg_resources dependency. Users
who need RESTinstance can install it separately.

Fixes #628

* docs: consolidate pyATS platform requirements in CHANGELOG

Move Windows and macOS/Python 3.12+ restrictions under the pyATS Integration
feature section since these are pyATS-specific requirements, not breaking
changes from nac-test 1.x.

* docs: clarify --minimal-reports applicability