[csharp] add .net9 support #5

[csharp] add .net9 support

Usage Workflow file

11 warnings

ubuntu-latest pipelines will use ubuntu-24.04 soon. For more details, see https://github.com/actions/runner-images/issues/10636

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L242

'ObjectWithDeprecatedFields.Bars' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L243

'ObjectWithDeprecatedFields.Bars' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L245

'ObjectWithDeprecatedFields.DeprecatedRef' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L246

'ObjectWithDeprecatedFields.DeprecatedRef' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L254

'ObjectWithDeprecatedFields.Bars' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L259

'ObjectWithDeprecatedFields.DeprecatedRef' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L120

'ObjectWithDeprecatedFields.Bars' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L121

'ObjectWithDeprecatedFields.DeprecatedRef' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs#L122

'ObjectWithDeprecatedFields.Id' is obsolete

Build: samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools.Test/Api/PetApiTests.cs#L93

'IPetApi.FindPetsByTagsAsync(List<string>, CancellationToken)' is obsolete

succeeded Dec 8, 2024 in 35s