Migrated to not released oapi-codegen 1.11.1 with implemented separated types

[sparshev]

The update a bit simplifies the oapi-codegen patch and makes sure we're still on track with them. Unfortunately the proposed patch is still not approved

Motivation and Context

Just in order to not get lost in time with using the external tools.

How Has This Been Tested?

Manually

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] I have signed the Adobe Open Source CLA.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.