Python detector does not match pre-release versions explicitly specified in requirements.txt

[cobya]

IPyPiClient when retrieving release information will not add pre-release versions to the list of potential versions (see IPyPiClient) to match requirements.txt versions to in PythonResolver.cs.

This leads to cases where pre-release versions are explicitly referenced in requirements.txt (ex. numpy 1.22.0rc3 when the current release version is 1.21.5) but the detector will output the selected version as the release version and not the pre-release.