includes a change to the format of cached information held about
individual packages

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

Remove implicit "allow-prereleases" in repository, consider explicit allow-prereleases in show, make search_for test in provider forward-compatible.

refactor(repository): always raise PackageNotFound in _get_page instead of returning None; remove unsuccessful attempt to get pretty name via json-based simple API

performance: cache pages of PyPI repository in the same way as for legacy repository to fix performance regression caused by replacing cachy

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

repository: according to PEP 440 pre-releases should be considered "if the only available version that satisfies the version specifier is a pre-release" (no special handling of "*" constraint)

Co-authored-by: David Hotham <david.hotham@blueyonder.co.uk>

MockEnv should not use paths of SystemEnv for paths that may be written to