tutorial: fix Kubernetes CRI interface link
The Kubernetes Container Runtime Interface document was moved to Adjust the URL in tutorial.md accordingly.
# cri-o Tutorial
-This tutorial will walk you through the installation of [cri-o](https://github.com/kubernetes-incubator/cri-o), an Open Container Initiative-based implementation of [Kubernetes Container Runtime Interface](https://github.com/kubernetes/kubernetes/blob/master/docs/proposals/container-runtime-interface-v1.md), and the creation of [Redis](https://redis.io/) server running in a [Pod](http://kubernetes.io/docs/user-guide/pods/).
+This tutorial will walk you through the installation of [cri-o](https://github.com/kubernetes-incubator/cri-o), an Open Container Initiative-based implementation of [Kubernetes Container Runtime Interface](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/container-runtime-interface-v1.md), and the creation of [Redis](https://redis.io/) server running in a [Pod](http://kubernetes.io/docs/user-guide/pods/).
## Prerequisites
