Update quickstart-onboard-github.md

Adding Note for restrictive GitHub repo onboarding to the quickstart page as well for more visibility to customers.

Author: j0tr

articles/defender-for-cloud/quickstart-onboard-github.md

@@ -25,6 +25,10 @@ By connecting your GitHub repositories to Defender for Cloud, you'll extend Defe
 - To use all advanced security capabilities provided by GitHub Connector in Defender for DevOps, you need to have GitHub Enterprise with GitHub Advanced Security (GHAS) enabled.
 
 ## Availability
+  > [!Note] 
+  > During the preview, the maximum number of GitHub repositories that can be onboarded to Microsoft Defender for Cloud is 2,000. If you try to connect more than 2,000 GitHub repositories, only the first 2,000 repositories, sorted alphabetically, will be onboarded.  
+  > 
+  > If your organization is interested in onboarding more than 2,000 GitHub repositories, please complete [this survey](https://aka.ms/dfd-forms/onboarding).
 
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