fix docker cache

Author: leepc12

.circleci/config.yml

@@ -66,7 +66,7 @@ jobs:
           name: build image
           command: |
             source ${BASH_ENV}
-            export DOCKER_CACHE_TAG=v2.2.2-cache2
+            export DOCKER_CACHE_TAG="WRN-503_ccd006dd-a484-4337-9754-fdf3d5b6d7b9"
             echo "pulling ${DOCKER_CACHE_TAG}!"
             docker pull encodedcc/chip-seq-pipeline:${DOCKER_CACHE_TAG}
             docker login -u=${DOCKERHUB_USER} -p=${DOCKERHUB_PASS}