Keep old version when creating a new one

.gitlab-ci.yml

 variables:
-  RELEASE_DIR: "release_target_211"
+  RELEASE_DIR: "public/release_target_211"
 
 pages:
   stage: deploy
@@ -9,9 +9,9 @@ pages:
   script:
     - mvn --version
     - mvn clean install   # build p2 repo
-    - rm -rf public
-    - mkdir -p "public/$RELEASE_DIR"
-    - cp -r de.hft-stuttgart.indriya.p2site/target/repository/* "public/$RELEASE_DIR"
+    - rm -rf $RELEASE_DIR
+    - mkdir -p $RELEASE_DIR
+    - cp -r de.hft-stuttgart.indriya.p2site/target/repository/* $RELEASE_DIR
   artifacts:
     paths:
       - public