Edit description of Update Iot Hub Resource Api

[harini-ms]

MSFT employees can try out our new experience at OpenAPI Hub - one location for using our validation tools and finding your workflow.

Changelog

Please ensure to add changelog with this PR by answering the following questions.

1. What's the purpose of the update?
   • new service onboarding
   • new API version
   • update existing version for new feature
   • update existing version to fix swagger quality issue in s360
   • Other, please clarify
     -Improve existing versions description by adding more details to the description.
2. When you are targeting to deploy new service/feature to public regions? Please provide date, or month to public if date is not available yet.
   Not Applicable, as update is for existing swagger versions
3. When you expect to publish swagger? Please provide date, or month to public if date is not available yet.
   Immediately, as update is for existing swagger versions
4. If it's an update to existing version, please select SDKs of specific language and CLIs that require refresh after swagger is published.
   • SDK of .NET (need service team to ensure code readiness)
   • SDK of Python
   • SDK of Java
   • SDK of Js
   • SDK of Go
   • PowerShell
   • CLI
   • Terraform
   • No, no need to refresh for updates in this PR
     Reason: No change in functionality, adding more details to the service side swagger.

Contribution checklist:

• I commit to follow the Breaking Change Policy of "no breaking changes"
• I have reviewed the documentation for the workflow.
• Validation tools were run on swagger spec(s) and errors have all been fixed in this PR. How to fix?