0.7.0

• Add Python 3.11 and django 4.1 support.
• Drop Python < 3.8 and Django < 2.2 support. #49
• Add pre-commit.
• Replace str.format with f-strings.
• Replace setup.py test in favor of runtests.py.
• Increase the size of the name and value_string fields to 255. #37
• Bump requirements and actions.