updated gitlab ci script

Change-Id: I1292bc864241d12593fdb8cc7d59343dc53cb752
diff --git a/gitlab-ci.yml b/gitlab-ci.yml
index b24e7c5..dfbfa29 100644
--- a/gitlab-ci.yml
+++ b/gitlab-ci.yml
@@ -41,8 +41,7 @@
     - apk update
     - apk add --no-cache xz
     - echo "$DOCKERHUB_TOKEN" | docker login -u "$DOCKERHUB_USERNAME" --password-stdin
-    - CLEAN_TAG=$(echo "${CI_COMMIT_TAG}" | sed 's/^[vV]//')
-    - echo ${CLEAN_TAG}
+    - CLEAN_TAG="${CI_COMMIT_TAG:1}"
     - ARTIFACT=kustvakt-${CLEAN_TAG}.tar.xz
     - xz -d -c "$ARTIFACT" | docker load
     - docker tag korap/kustvakt:$CLEAN_TAG korap/kustvakt:latest