handle value error if version can't be parsed

[aliasaria]

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Why are these changes needed?

Dev versions of Huggingface Transformers may look like "4.50.0.dev0" which break FastChat because it expects the format to be only like 4.50.0 etc.

This is necessary, for example, to support the new Gemma models when they are released, because they only work with a dev build of Transformers