Add VersionWithSource type to py-rattler

[Wackyator]

No description provided.

[wolfv]

I think if we add a VersionBase class in Python we can get away with implementing the forwarding functions for a few things only once.

E.g.

class VersionBase:
    @property
    def epoch(self) -> Optional[str]:
        """
        Gets the epoch of the version or `None` if the epoch was not defined.

        Examples
        --------
        >>> v = Version('2!1.0')
        >>> v.epoch
        2
        """
        return self._version.epoch()

    @property
    def has_local(self) -> bool:
        """
        Returns true if this version has a local segment defined.
        The local part of a version is the part behind the (optional) `+`.

        Examples
        --------
        >>> v = Version('1.0+3.2-alpha0')
        >>> v.has_local
        True
        >>> v2 = Version('1.0')
        >>> v2.has_local
        False
        """
        return self._version.has_local()

If both, Version and VersionWithSource call the inner type _inner you can align the two, and inherit with both from VersionBase. That should remove some (trivial) duplication.

[baszalmstra]

Instead of having a VersionBase, wouldnt it be possible to have a Version and a VersionWithSource that derives from Version and adds a source string? Thats essentially what it is.

[baszalmstra]

I like this approach but it raises the question: do we even need the PyVersionWithSource?