Add allow-prereleases input

In scope of this release we added a new input (allow-prereleases) to allow falling back to pre-release versions of Python when a matching GA version of Python is not available

steps:
  - uses: actions/checkout@v3
  - uses: actions/setup-python@v4
    with:
      python-version: 3.12
      allow-prereleases: true

Besides, we added such changes as:

• Fix bug to trim new line for PyPy version: #610
• Added pip dependency file to generate hash from it: #604
• Improved error handling for saving and restoring cache: #618
• Add warning if cache paths are empty: #642