fix: ignore warning for gem install

We are installing from a gem file directly so there is no need to specify a version

.gitlab-ci.yml

@@ -19,6 +19,6 @@ docker_lint:
   image: hadolint/hadolint:latest-debian
   script:
     # Ignoring DL3008 - Pin Versions of apt-get modules
-    - hadolint --ignore DL3008 Dockerfile
+    - hadolint --ignore DL3008 --ignore DL3028 Dockerfile
   tags:
     - nexus_runner