RHDEVDOCS 6356 add pipelines-docs-1.18 to distromap

Author: mramendi

_distro_map.yml

@@ -428,6 +428,9 @@ openshift-pipelines:
     pipelines-docs-1.17:
       name: '1.17'
       dir: pipelines/1.17
+    pipelines-docs-1.18:
+      name: '1.18'
+      dir: pipelines/1.18
 openshift-builds:
   name: builds for Red Hat OpenShift
   author: OpenShift documentation team <openshift-docs@redhat.com>