Update SharpYaml dependency to v3.x

Is your feature request related to a problem? Please describe.

OpenAPI.NET currently depends on SharpYaml v2. In my project, I use OpenAPI.NET to process OpenAPI documents and also need to read additional YAML-based configuration files.

SharpYaml v3 is a major redesign that introduces breaking changes compared to v2. Since OpenAPI.NET brings SharpYaml v2 as a dependency, I am currently forced to continue developing against the older SharpYaml API and plan a future migration.

Describe the solution you'd like

I would like OpenAPI.NET to update its SharpYaml dependency from v2 to the latest v3 release.

Describe alternatives you've considered

• Continuing to use SharpYaml v2 in my own code and migrating later.
• Isolating YAML processing behind an abstraction layer to minimize the impact of a future migration.
• Using a different YAML library for application-specific configuration files.

While these approaches are possible, they add complexity that could be avoided if OpenAPI.NET adopted SharpYaml v3 directly.

Xác định khai báo dependency của project cho SharpYaml v2 và xem xét các breaking changes của SharpYaml v3 trước khi đánh giá việc xử lý YAML của OpenAPI bị ảnh hưởng. Chạy test suite hiện có sau khi cập nhật dependency; hoàn tất nghĩa là SharpYaml v3 được sử dụng và việc xử lý YAML của tài liệu OpenAPI vẫn tương thích.