create tar.gz artifacts

Change-Id: I5efb6fe2475093ac4a146dc6fd4c675ec4412744
diff --git a/generate-cookiecutter-products.groovy b/generate-cookiecutter-products.groovy
index 8abe4c5..641689e 100644
--- a/generate-cookiecutter-products.groovy
+++ b/generate-cookiecutter-products.groovy
@@ -131,7 +131,8 @@
                     git.commitGitChanges(modelEnv, "Added new cluster ${clusterName}")
                     git.pushGitChanges(modelEnv, targetBranch, 'origin', RECLASS_MODEL_CREDENTIALS)
                 }
-                archiveArtifacts artifacts: modelEnv
+                sh(returnStatus: true, script: "tar zcvf ${clusterName}.tar.gz ${modelEnv}")
+                archiveArtifacts artifacts: "${clusterName}.tar.gz"
             }
 
         } catch (Throwable e) {