Fix performance bug in get stats

• Fix performance bug in get stats
• Move to pytoml build
• Adjust to pytrafficgen 4.0 (affects mainly testing)

3.2.2

• Run pre-commit with isort/black/flake8/pylint/mypy.
• Fix sample and tests.
• Run all tests against STC 5.21.

3.2.0

• Add github Python package action
• isort and flake8