chore(deps): bump transformers in /integration/BitNet

Bumps [transformers](https://github.com/huggingface/transformers) from 4.40 to 4.50.0.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](huggingface/transformers@v4.40.0...v4.50.0)

---
updated-dependencies:
- dependency-name: transformers
  dependency-version: 4.50.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

integration/BitNet/requirements.txt

@@ -1,3 +1,3 @@
 lm_eval==0.3.0
 flash_attn
-transformers==4.40
+transformers==4.50.0