use simpler syntax to limit jobs by tag pushes

.gitlab-ci.yml

@@ -128,8 +128,7 @@ package:
   environment:
     name: release
   only:
-    variables:
-      - $CI_COMMIT_TAG
+    - tags
   interruptible: true
   extends:
     .set-helm-version
@@ -144,8 +143,7 @@ upload:
   environment:
     name: release
   only:
-    variables:
-      - $CI_COMMIT_TAG
+    - tags
   interruptible: true
   extends:
     .set-helm-version
@@ -160,8 +158,7 @@ release:
   environment:
     name: release
   only:
-    variables:
-      - $CI_COMMIT_TAG
+    - tags
   interruptible: true
   # script or trigger is required :/
   script: