Update proposals/incubation/kubeflow.md

Co-authored-by: Yuan Tang <[email protected]>
Signed-off-by: Ricardo Rocha <[email protected]>

proposals/incubation/kubeflow.md

@@ -133,6 +133,7 @@ The Kubeflow community includes a variety of Slack forums for general discussion
 * Pipelines - [https://github.com/kubeflow/pipelines/issues](https://github.com/kubeflow/pipelines/issues)
 * Training-operator - [https://github.com/kubeflow/training-operator/issues](https://github.com/kubeflow/training-operator/issues)
 * Katib - [https://github.com/kubeflow/katib/issues](https://github.com/kubeflow/katib/issues)
+* MPI Operator - [https://github.com/kubeflow/mpi-operator/issues](https://github.com/kubeflow/mpi-operator/issues)
 
 ## Community