Add .NET SDK to metadata.yaml

Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Sabelnikov, Dmitriy <dmitriy.sabelnikov@t-systems.com>
Co-committed-by: Sabelnikov, Dmitriy <dmitriy.sabelnikov@t-systems.com>

metadata.yaml

@@ -923,6 +923,13 @@ categories:
           link: /object-storage-service-3rd-party/python-sdk/
           hc_location: sdk/python-devg-obs
           disable_import: false
+        - html_location: docs/obs_3rd_party/dotnet_sdk
+          rst_location: doc/dotnet-sdk/source
+          title: .NET SDK
+          type: dotnet-sdk
+          link: /object-storage-service-3rd-party/dotnet-sdk/
+          hc_location: sdk/dotnet-devg-obs
+          disable_import: false
       teams:
         - name: docs-storage-rw
           permission: write