Update container-registry-tutorial-sign-build-push.md

We released a patch for the [Notation-Azure-KV plugin](https://github.com/Azure/notation-azure-kv/releases/tag/v0.3.1-alpha.1) yesterday. So we need to upgrade the Notation-Azure-KV plugin version from `v0.3.0-alpha.1` to `v0.3.1-alpha.1` in Azure Documentation.

Author: FeynmanZhou

articles/container-registry/container-registry-tutorial-sign-build-push.md

@@ -56,7 +56,7 @@ In this tutorial:
     
     # Download the plugin
     curl -Lo notation-azure-kv.tar.gz \
-        https://github.com/Azure/notation-azure-kv/releases/download/v0.3.0-alpha.1/notation-azure-kv_0.3.0-alpha.1_Linux_amd64.tar.gz
+        https://github.com/Azure/notation-azure-kv/releases/download/v0.3.1-alpha.1/notation-azure-kv_0.3.1-alpha.1_Linux_amd64.tar.gz
     
     # Extract to the plugin directory
     tar xvzf notation-azure-kv.tar.gz -C ~/.config/notation/plugins/azure-kv notation-azure-kv
@@ -248,4 +248,4 @@ notation verify $IMAGE
 
 ## Next steps
 
-[Enforce policy to only deploy signed container images to Azure Kubernetes Service (AKS) utilizing **ratify** and **gatekeeper**.](https://github.com/Azure/notation-azure-kv/blob/main/docs/nv2-sign-verify-aks.md)
+[Enforce policy to only deploy signed container images to Azure Kubernetes Service (AKS) utilizing **ratify** and **gatekeeper**.](https://github.com/Azure/notation-azure-kv/blob/main/docs/nv2-sign-verify-aks.md)