Font-v

- `get_git_root_path` now searches up to five directory levels for the root .git directory path before failing (broadens suppport for more deeply nested font paths)
- update fonttools dependency to v4.28.2

- drop support for Python interpreters < 3.7 (dropped by our fonttools dependency)
- drop Py 3.6 CI testing
- add Py 3.10 CI testing
- transition GitHub Actions workflows to Python 3.10 interpreter default
- use Py 3.10 in tox.ini config
- remove OpenFV spec references from source and repository documentation
- udpate fonttools dependency to v4.28.1
- update gitdb dependency to v4.0.9
- update gitpython dependency to v3.1.24
- update smmap dependency to v5.0.0

- add Python 3.9 classifier to `setup.py`
- minor `setup.py` source formatting updates
- update fonttools dependency to v4.17.0
- update gitpython dependency to v3.1.11

- add cPython 3.9 interpreter testing
- add CodeQL testing
- update fonttools dependency to v4.16.1
- update gitpython dependency to v3.1.10

- update fonttools dependency to v4.14.0
- update gitdb dependency to v4.0.5
- update gitpython dependency to v3.1.8
- update smmap dependency to v3.0.4
- transition CI testing to the GitHub Actions service

- add Production/Stable classifier to `setup.py`
- remove Python < 3.6 classifiers from `setup.py`
- add Python 3.7, Python 3.8 classifiers to `setup.py`