Update .gitlab-ci.yml

.gitlab-ci.yml

 #image: python:alpine
 image: centos:latest
 
+# Cache modules in between jobs
+cache:
+  key: ${CI_COMMIT_REF_SLUG}
+  paths:
+  - data/
+
+before_script:
+  - touch data/truc.txt
+
+step1:
+  script:
+  - ls data
+
 ## integrate k8s cluster
 deploy to staging:
 #  stage: deploy