[docs] print dependencies in Documentation job (ray-project#36683)

Signed-off-by: Matthew Deng <[email protected]>

.buildkite/pipeline.build.yml

@@ -458,6 +458,7 @@
  # See https://stackoverflow.com/questions/63383400/error-cannot-uninstall-ruamel-yaml-while-creating-docker-image-for-azure-ml-a
  # Pin urllib to avoid downstream ssl incompatibility issues. This matches requirements-doc.txt.
  - pip install "mosaicml==0.12.1" "urllib3<1.27" --ignore-installed
+ - ./ci/env/env_info.sh
  - ./ci/ci.sh build_sphinx_docs
 
 - label: ":octopus: Tune multinode tests"