python 3.8 compatibility

[pokulo]

Description

This package is not compatible with Python 3.8 since commit e691d5a, see e.g.:

Traceback (most recent call last):
  File "/home/…/.local/bin/http_converter", line 5, in <module>
    from http_converter import main
  File "/home/…/.local/pipx/venvs/errno_converter/lib/python3.8/site-packages/http_converter.py", line 4, in <module>
    from lib.converter import Converter
  File "/home/…/.local/pipx/venvs/errno_converter/lib/python3.8/site-packages/lib/converter.py", line 5, in <module>
    class Converter(object, metaclass=abc.ABCMeta):
  File "/home/…/.local/pipx/venvs/errno_converter/lib/python3.8/site-packages/lib/converter.py", line 26, in Converter
    def get_candidates() -> list[str]:
TypeError: 'type' object is not subscriptable

Affected Version

Commit e691d5a changed app version in pyproject.toml to 0.1.5. But git version tags are missing!

Proposed Solution

This could be solved by using backported typing imports like this one:

from __future__ import annotations

[pokulo]

python 3.8 ist EOL. so the pyproject.toml might just raise compatibility flag to python 3.9 and later.