gguf-py : bump sentencepiece version (#19319)
* gguf-py: Bump sentencepiece version
There's a new version that's been out for a while that addresses the issues mentioned in https://github.com/ggml-org/llama.cpp/pull/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.
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