Upgrade dependency on sentencepiece

[BLKSerene]

Hi, sentencepiece 0.2.1 has just been released, so this PR upgrades the dependency on sentencepiece.

And to simplify future maintenance work, this PR also makes the version pin less stricter.

[rltgjqmcpgjadyd]

This PR needs to be merged to resolve this issue. #493

[LiJT]

Yes please!!!! ComfyUI newest 3.13 python need this PR so bad!!!!!!!!

[bytimer]

I do this to solve it:
Download argostranslate-1.9.6-py3-none-any.whl from https://pypi.org/project/argostranslate/#files

install wheel
.\python_embeded\python.exe -m pip install wheel

unpack the .whl
\python_embeded\Scripts\wheel.exe unpack argostranslate-1.9.6-py3-none-any.whl

Edit : argostranslate-1.9.6\argostranslate-1.9.6.dist-info\METADATA
find : Requires-Dist: sentencepiece (==0.2.0)
modify : Requires-Dist: sentencepiece (>=0.2.0)

repack to .whl
cd argostranslate-1.9.6
\python_embeded\Scripts\wheel.exe pack .

now pip install the new .whl
.\python_embeded\python.exe -m pip install "O:\argostranslate-1.9.6-py3-none-any.whl"

all OK.