Remove `transformers` from model tags

According to [this comment](https://github.com/huggingface/huggingface.js/pull/1826#issuecomment-3488286125), Chronos-2 is not natively supported by `transformers`. To avoid the confusion, I suggest to remove it from the model card tags. Model won't be listed in the [transformers-compatible models](https://huggingface.co/models?library=transformers) and won't have the `transformers` snippet in "use this model".

README.md

@@ -6,7 +6,6 @@ tags:
   - forecasting
   - foundation models
   - pretrained models
-  - transformers
   - safetensors
 paper:
   - https://arxiv.org/abs/2510.15821