Merge remote-tracking branch 'origin/master'

README.md

+## Usage for test and deploy
+
+* You can set the CI/CD variable `COMPOSER_DOWNGRADE` to `1` for using the composer version 1. Default is composer version 2.
+* For authenticating with the Gitlab package repository, you have to set the variable `GITLAB_ACCESS_TOKEN`, which you have to create for the user who runs the pipeline.
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