Update curated packages doc to include subscription steps for release alerts (#9731)

Author: jhaanvi5

docs/content/en/docs/packages/whatsnew/_index.md

@@ -0,0 +1,8 @@
+---
+title: "What's New"
+linkTitle: "What's New"
+weight: 15
+description: >
+  New EKS Anywhere Curated Packages releases, features, and fixes
+---
+

docs/content/en/docs/packages/changelog.md renamed to docs/content/en/docs/packages/whatsnew/changelog.md

@@ -0,0 +1,28 @@
+---
+title: "Release Alerts"
+weight: 60
+aliases:
+    /docs/reference/snsupdates/
+description: >
+  SNS Alerts for EKS Anywhere Curated Packages releases
+---
+
+EKS Anywhere uses Amazon Simple Notification Service (SNS) to notify availability of a new releasef for Curated Packages.
+It is recommended that your clusters are kept up to date with the latest EKS Anywhere Curated Packages.
+Please follow the instructions below to subscribe to SNS notification.
+
+* Sign in to your AWS Account
+* Select us-east-1 region
+* Go to the SNS Console
+* In the left navigation pane, choose "Subscriptions"
+* On the *Subscriptions* page, choose "Create subscription"
+* On the *Create subscription* page, in the *Details* section enter the following information
+  * Topic ARN
+    ```
+    arn:aws:sns:us-east-1:153288728732:eks-anywhere-curated-packages-bundle-updates
+    ```
+  * Protocol - *Email*
+  * Endpoint - *Your preferred email address*
+* Choose *Create Subscription*
+* In few minutes, you will receive an email asking you to confirm the subscription
+* Click the confirmation link in the email