RHDEVDOCS-5695 Update _distro_map.yml

Author: Srivaralakshmi

_distro_map.yml

@@ -345,6 +345,9 @@ openshift-gitops:
     gitops-docs-1.12:
       name: '1.12'
       dir: gitops/1.12
+    gitops-docs-1.13:
+      name: '1.13'
+      dir: gitops/1.13
 openshift-pipelines:
   name: Red Hat OpenShift Pipelines
   author: OpenShift documentation team <openshift-docs@redhat.com>