Requirements parsing error on some non-normalized spellings in version selection

This issue was migrated from `gh-action-pip-audit`, since the bug being reported isn't in the action itself.



Upstream tracking: https://github.com/pypa/packaging/issues/653



---



Running the following .yml file results in the following error. I am currently trying to troubleshoot an error flagged by `pip-audit` for [`setuptools`](https://github.com/pypa/pip-audit/pull/454) in the CI environment, and it is likely that `setuptools` is getting flagged by `pip-audit` still, before running into this error.

```

jobs:

  pip-audit:

    runs-on: ubuntu-latest



    steps:

      - name: Checkout

        uses: actions/checkout@v2



      - name: Run pip-audit

        uses: pypa/gh-action-pip-audit@v1.0.4

        with:

          inputs: requirements-dev.txt

          ignore-vulns: PYSEC-2021-427

```





```

Traceback (most recent call last):

  File "/home/runner/work/_actions/pypa/gh-action-pip-audit/v1.0.4/action.py", line 138, in <module>

    with open("/tmp/pip-audit-output.txt", "r") as io:

FileNotFoundError: [Errno 2] No such file or directory: '/tmp/pip-audit-output.txt'

```

[]