Update .gitlab-ci.yml to updates in the post

.gitlab-ci.yml

@@ -10,10 +10,8 @@ pages:
     - composer
   script:
   - if [ ! -d composer ]; then mkdir composer; fi
-  - echo "$AUTH_JSON" > composer/auth.json
-  - docker run --rm -i -v `pwd`:/build -v `pwd`/composer:/composer composer/satis
+  - docker run --rm -i -v `pwd`:/build -v `pwd`/composer:/composer -e COMPOSER_AUTH="$COMPOSER_AUTH" composer/satis
   - mv output public # gitlab requires directory to be named public
-  - rm -f composer/auth.json # don't store auth
   artifacts:
     paths:
     - public