Document using openshift-cherrypick-robot

Signed-off-by: John Fulton <[email protected]>

docs/contributing/cherry-picking.md

@@ -14,7 +14,25 @@ cherry pick.
 
 Please do not ask [core maintainers](../../OWNERS) to cherry pick your
 patch though we will be happy to review it and help merge it once the
-cherry pick PR has been submitted.
+cherry pick PR has been submitted using one of the methods below.
+
+## Method 1
+
+Add a comment like the following to the PR you wish to cherry pick.
+```
+/cherrypick 18.0.0-proposed
+```
+The [openshift-cherrypick-robot](https://github.com/openshift-cherrypick-robot)
+will then attempt to create a new PR of the original PR (after it
+merges) with a cherry-pick of the same patch into the desired branch.
+There are
+[examples](https://github.com/openstack-k8s-operators/architecture/pull/395#issuecomment-2352668300)
+of this in previous PRs in this repository.
+
+If there is a [merge conflict](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/addressing-merge-conflicts/resolving-a-merge-conflict-using-the-command-line),
+then method 1 will not work and you will need to use method 2.
+
+## Method 2
 
 If you can send a PR to this repository then you can create a cherry
 pick using the `git` command line tools without requiring any