[EKS] [request]: Add changelog url to EKS APIs like DescribeClusterVersions and DescribeAddonVersions

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**Tell us about your request**

The API to retrieve versions are great and super handy. At least we could programmatically now bump our Clusters and Addons.

The ask ti to add a `changelogUrl` for API [DescribeClusterVersions](https://docs.aws.amazon.com/eks/latest/APIReference/API_DescribeClusterVersions.html) and for API [DescribeAddonVersions](https://docs.aws.amazon.com/eks/latest/APIReference/API_DescribeAddonVersions.html)

**Which service(s) is this request for?**
EKS and EKS addons

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.

We do not blindly apply all the changes, but there is some process behind cluster upgrade or addon upgrade. Having a changelog provide following benefits

- Provides clear communication about changes made to software, features, and bug fixes.
- Allows users to plan for updates and upgrades.
- Helps pinpoint the root cause of issues by tracking changes made to the codebase.
- Simplifies debugging and|or rollback processes.
- A changelog is essential for compliance with regulations and auditing requirements.
- Dependency update tools can pick up this changelog and help us to improve our automation processes

We do GitOps, and before applying changes, we would like to know
- New Features: Describe new functionalities added to the software.
- Bug Fixes: Detail resolved issues and their impact.
- Improvements: Outline enhancements to existing features or performance.
- Breaking Changes: Highlight any changes that may affect existing functionality.

Currently eks addons have two versions addon itself and build version like `v2.6.0-eksbuild.1`, and is quite hard to understand what the changes are, are there are new values supported, or different defaults. We have policies as code, and sometimes things breaks and it's this could improve certain things

**Are you currently working around this issue?**
How are you currently solving this problem?

Keeping links in bookmarks.

**Additional context**
Anything else we should know?

**Attachments**
If you think you might have additional information that you'd like to include via an attachment, please do - we'll take a look. (Remember to remove any personally-identifiable information.)

Start by reviewing the AWS API documentation for DescribeClusterVersions and DescribeAddonVersions linked in the issue. The request is complete when both APIs expose a changelogUrl that lets users find version changes for EKS clusters and add-ons.

Written by the indexing model from the issue text.