add hf cache caching for GHA (#2247)

* add hf cache caching for GHA

* use modal volume to cache hf data

* make sure to update the cache as we add new fixtures in conftest

cicd/Dockerfile.jinja

@@ -8,6 +8,7 @@ ENV PYTORCH_VERSION="{{ PYTORCH_VERSION }}"
 ENV GITHUB_REF="{{ GITHUB_REF }}"
 ENV GITHUB_SHA="{{ GITHUB_SHA }}"
 ENV NIGHTLY_BUILD="{{ NIGHTLY_BUILD }}"
+ENV HF_HOME="{{ HF_HOME }}"
 
 RUN apt-get update && \
     apt-get install -y --allow-change-held-packages vim curl nano libnccl2 libnccl-dev