Pre-commit hook for poetry-export should use same sort strategy as pre-commit/requirements-txt-fixer

• I have searched the issues of this repo and believe that this is not a duplicate.
• I have searched the FAQ and general documentation and believe that my question is not already covered.

Feature Request

Pre-commit is excellent for standardizing checks across an organization's repositories. There's a conflict when trying to use poetry-export with pre-commit/requiremenets-txt-fixer as they sort differently.

E.g. the poetry-export hook will put pytest-cov above pytest, while pre-commit/requirements-txt-fixer will do the opposite.

While some may argue to "use one or the other", that makes it difficult to share a standardized .pre-commit-config.yaml across all repos of an org for consistency. Some repos may be currently using poetry or not or are slowing transitioning to use it.

This request is related to python-poetry/poetry#6944

Start by comparing the poetry-export pre-commit hook with pre_commit_hooks/requirements_txt_fixer.py, which the issue identifies as the desired sorting reference. Reproduce the pytest/pytest-cov ordering difference, then locate the hook's existing tests or entry point. Done means poetry-export produces the same ordering strategy as requirements-txt-fixer and the example is covered by a test.