Login to docker registry to push image(s)

Change-Id: I9c9517f2c0c8e1c182d30ecb22d1fd6fee12866f
See: https://mirantis.jira.com/browse/PROD-23577
diff --git a/docker-mirror-images.groovy b/docker-mirror-images.groovy
index d88c9d1..92fea8e 100644
--- a/docker-mirror-images.groovy
+++ b/docker-mirror-images.groovy
@@ -64,7 +64,9 @@
                     // https://github.com/jenkinsci/docker-workflow-plugin/blob/docker-workflow-1.17/src/main/resources/org/jenkinsci/plugins/docker/workflow/Docker.groovy#L168-L170
                     sh("docker tag ${srcImage.id} ${targetImageFull}")
                     common.infoMsg("Attempt to push docker image into remote registry: ${env.REGISTRY_URL}")
-                    sh("docker push ${targetImageFull}")
+                    docker.withRegistry(env.REGISTRY_URL, env.TARGET_REGISTRY_CREDENTIALS_ID) {
+                        sh("docker push ${targetImageFull}")
+                    }
                     if (targetImageFull.contains(externalMarker)) {
                         external = true
                     }