title: How to append the new tag to the list of existing tag in the yaml file using groovy/pipeline script
body: <p>I have a yaml file(config.yaml) with tags/structure similar to what is mentioned below. I need to add a new tenant(tenant3) to the list of the existing tenants. How do I achieve it using the pipeline/groovy script? Any help/lead would be appreciated.</p>
  <pre><code>consumer_services:
  - security
  - token
  id: 10000
  tenants:
    tenant_1:
      state: all
      web_token: true
      cluster_pairs:
      - cluster1
      datacenter: local
      client: CLIENT_TEST
    tenant_2:
      state: all
      web_token: true
      cluster_pairs:
      - cluster2
      datacenter: local
      client: CLIENT_TEST
  base_network:
      subnets:
      - 10.160.10.10
      - 10.179.1.09
  </code></pre>