Use git strategy "fetch"

.gitlab-ci.yml

@@ -15,9 +15,8 @@ build:
   stage: build
   image: composer:1
   variables:
-    GIT_STRATEGY: "none"
+    GIT_STRATEGY: "fetch"
   before_script:
-  - apk add bash --update
   - export COMPOSER_CACHE_DIR=/cache/composer
   - composer config store-auths false
   - composer config http-basic.git-t3o.typo3.org gitlab-ci-token ${CI_BUILD_TOKEN}