Task list for VK_QCOM_ycbcr_degamma release

Allows implementations to apply sRGB degamma (sRGB EOTF) to YCbCr format images during texture filtering by extending `VkSamplerYcbcrConversionCreateInfo`. The degamma can be selectively applied to the Y (luma) and/or CbCr (chroma) components, enabling texture filtering to operate in linear space and improving quality for camera YCbCr images encoded with an sRGB or gamma 2.2 transfer function.

The task list for the VK_QCOM_ycbcr_degamma release is:

- [x] Vulkan Specification: https://docs.vulkan.org/refpages/latest/refpages/source/VK_QCOM_ycbcr_degamma.html
- [x] Validation layer: https://github.com/KhronosGroup/Vulkan-ValidationLayers/pull/12942

As each component is made public, the task will be checked off. When all tasks have been completed this issue will be closed and the extension will be fully released.

Review the VK_QCOM_ycbcr_degamma specification page and the referenced validation-layer pull request, then compare them with the unchecked items in the release task list. Done means every release component is public and all task-list entries can be checked before closing the issue.

Written by the indexing model from the issue text.