This change adds additional build dependencies accidentally missed in
the previous commit.
Although the devel/py-setuptools dependency is technically redundant in
light of devel/py-setuptools-scm, it's best to express all of the needed
dependencies in BUILD_DEPENDS.
Adjust PYTHON_USES to only permit 3.11+ given the change introduced in
the pyproject.toml file upstream, while here.
Reported by: poudriere
Pointyhat to: ngie
Fixes: 59337d86174 ("devel/ghpr: update to v3")