gguf-py: Bump sentencepiece version

[Ahajha]

There's a new version that's been out for a while that addresses the issues mentioned in #14200. There's a long chain of reasons I would like this change, but the short version is that it allows people who use both sentencepiece and gguf to take advantage of these fixes. On conda-forge, currently, it locks the version (since there is no notion of optional dependencies).

Regardless, I don't think this should be too controversial.

[CISC]

Thank you, could you also update requirements/requirements-convert_legacy_llama.txt?

[ehoogeveen-medweb]

The range for sentencepiece in pyproject.toml was updated from
sentencepiece = ">=0.1.98,<0.2.0"
to
sentencepiece = ">=0.1.98,<=0.2.0"
in #5664

But I wonder if this was intentional or if the intent was simply to allow 0.2.0 (the latest version at the time) and the actual range should have been
sentencepiece = ">=0.1.98,<0.3.0"
to align with semantic versioning (where versions <1.0 use the convention 0.major.minor, so 0.3.0 would be a major release with breaking changes while 0.2.x are minor releases).