fix creds in .gitlab-ci.yml

.gitlab-ci.yml

@@ -3,7 +3,7 @@ stages:
 
 before_script:
   # auth docker registry before using it
-  - echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$KSZK_NEXUS_USERNAME\",\"password\":\"$KSZK_NEXUS_PASSWORD\"}}}"
+  - echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}"
     > /kaniko/.docker/config.json
 
 ###################### Image builder template #####################