adding abi3-py38 compatibility for python wheel

[luccabb]

Summary

This PR relies on abi3 to build a python module that can be used on multiple python versions. Before this PR, gni's python module was only compatible with the exact python version it was compiled against.

whats abi3?

PEP 384 defines a limited python API with a stable ABI (aka abi3), this limited ABI works across multiple python versions.

Test Plan

Before

build on py310 env:

$ python -c 'import sys; print(sys.version_info[:])'
(3, 10, 12, 'final', 0)
$ maturin build --release --features=python
…
📦 Built wheel for CPython 3.10 to /path/to/310.whl

install on py39 env:

$ python -c 'import sys; print(sys.version_info[:])'
(3, 9, 17, 'final', 0)
$ pip install /path/to/310.whl
...
ERROR: 310.whl is not a supported wheel on this platform.

After

build on py310 env:

$ python -c 'import sys; print(sys.version_info[:])'
(3, 10, 12, 'final', 0)
$ maturin build --release --features=python
…
📦 Built wheel for CPython 3.10 to /path/to/310.whl

install on py39 env:

$ python -c 'import sys; print(sys.version_info[:])'
(3, 9, 17, 'final', 0)
$ pip install /path/to/310.whl
…
$ python -c 'import gni_lib; print(gni_lib.get_gpu_node_id())'
<id>

[A-Kokolis]

why do you want to downgrade here?
The default version in fbcode is 3.10 https://fburl.com/wiki/7q6e07my

[luccabb]

as a result of "abi3-py38" it should be compatible with any version >= python 3.8. so removed the artificial restriction on pyproject.toml