Add unmaintained notice to contrib flink (#2319)

Signed-off-by: Anna Jung (VMware) <antheaj@vmware.com>

Signed-off-by: Anna Jung (VMware) <antheaj@vmware.com>

contrib/flink/README.md

@@ -0,0 +1,7 @@
+Please note: This component is **unmaintained and out-of-date**.
+
+If the component fails to meet the [contrib requirements](https://github.com/kubeflow/manifests/blob/master/proposals/20220926-contrib-component-guidelines.md#component-requirements)
+ by the next Kubeflow release ([1.7](https://github.com/kubeflow/community/tree/master/releases/release-1.7#timeline)),
+ it will be removed from the [`manifest`](https://github.com/kubeflow/manifests) repository.
+
+Updates to the `/contrib` components can be found in the [tracking issue](https://github.com/kubeflow/manifests/issues/2311).