Update Dockerfile - flash-attn

Dockerfile

@@ -22,6 +22,10 @@ RUN cd lm-evaluation-harness && pip install -e ".[vllm]"
 RUN cd cot-eval && pip install -e .
 RUN pip install -U vllm==${VLLM_VERSION}
 
+# reinstall flash-attn as torch might have gotten reinstalled above
+RUN pip uninstall -y flash-attn
+RUN pip install flash-attn --no-build-isolation
+
 
 # Environment variables