Add description in azure-eventgrid to tell users to use azure-messaging-eventgrid (#22326)

Author: YijunXieMS

eng/versioning/version_data.txt

@@ -38,7 +38,7 @@ com.microsoft.azure:azure-servicebus;3.6.3;3.6.4
 com.microsoft.azure:azure-storage;8.6.5;8.6.5
 com.microsoft.azure:azure-storage-blob;11.0.2;11.0.2
 com.microsoft.azure.msi_auth_token_provider:azure-authentication-msi-token-provider;1.1.0-beta.1;1.1.0-beta.1
-com.microsoft.azure:azure-eventgrid;1.4.0-beta.1;1.4.0-beta.1
+com.microsoft.azure:azure-eventgrid;1.4.0-beta.1;1.4.0
 com.microsoft.azure:azure-loganalytics;1.0.0-beta-2;1.0.0-beta.2
 com.microsoft.azure:azure-media;1.0.0-beta.1;1.0.0-beta.1
 com.microsoft.azure:microsoft-azure-storage-perf;1.0.0-beta.1;1.0.0-beta.1

sdk/eventgrid/microsoft-azure-eventgrid/README.md

@@ -1,5 +1,6 @@
 # Azure Event Grid
-
+> Please note, a newer package [com.azure:azure-messaging-eventgrid](https://search.maven.org/artifact/com.azure/azure-messaging-eventgrid) for [Azure EventGrid](https://docs.microsoft.com/azure/event-grid/) is available as of March 2021. While this package will continue to receive critical bug fixes, we strongly encourage you to upgrade. Read the [migration guide](https://aka.ms/azsdk/java/migrate/eg) for more details.
+> 
 This project provides client tools or utilities in Java that make it east to interact with [Azure Event Grid](https://azure.com/eventgrid). For documentation please see the Microsoft Azure [Java Developer Center](https://azure.microsoft.com/develop/java/) or the [JavaDocs](https://azure.github.io/azure-sdk-for-java/).
 
 Azure Event Grid is a fully-managed intelligent event routing service that allows for uniform event consumption using a publish-subscribe model.
@@ -21,7 +22,7 @@ To get the binaries of the official Microsoft Azure Event Grid Java SDK as distr
 <dependency>
     <groupId>com.microsoft.azure</groupId>
     <artifactId>azure-eventgrid</artifactId>
-    <version>1.4.0-beta.1</version>
+    <version>1.4.0</version>
 </dependency>
 ```
 [//]: # ({x-version-update-end})

sdk/eventgrid/microsoft-azure-eventgrid/pom.xml

@@ -10,7 +10,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.microsoft.azure</groupId>
     <artifactId>azure-eventgrid</artifactId>
-    <version>1.4.0-beta.1</version> <!-- {x-version-update;com.microsoft.azure:azure-eventgrid;current} -->
+    <version>1.4.0</version> <!-- {x-version-update;com.microsoft.azure:azure-eventgrid;current} -->
     <packaging>jar</packaging>
     <name>Microsoft Azure SDK for eventgrid</name>
     <description>This package contains Microsoft Azure EventGrid SDK.${line.separator}