Update compiled-languages-csharp.md

Author: felickz

troubleshooting/codeql-builds/compiled-languages-csharp.md

@@ -57,14 +57,22 @@ This can indicate your custom package server is not configured which may fail th
 
 #### NuGet.targets(132,5): warning : Your request could not be authenticated by the GitHub Packages service. Please ensure your access token is valid and has the appropriate scopes configured.
 
-Consider adding auth for your GitHub Packages hosted NuGet feed using the nuget CLI tooling.  Add this before the `autobuild` / custom build steps in your workflow.
+The actions/setup-dotnet action supports [setting up authentication for nuget feeds](https://github.com/actions/setup-dotnet#setting-up-authentication-for-nuget-feeds). Add this before the `autobuild` / custom build steps in your workflow:
+```yml
+- uses: actions/setup-dotnet@v3
+  with:
+    source-url: https://nuget.pkg.github.com/<owner>/index.json
+  env:
+    NUGET_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+```
+
+Alternatively, consider adding auth for your GitHub Packages hosted NuGet feed using the nuget CLI tooling.  
 
 ```yml 
   - name: add nuget auth
     run: dotnet nuget add source https://nuget.pkg.github.com/<org-goes-here>/index.json -n "GitHub" -u USERNAME -p "${{ secrets.GH_PACKAGES_READ_ONLY }}" --store-password-in-clear-text
  ```
 
-
 ### .NET Framework 
 
 #### NuGet Authentication