Raise various required minimum versions for OCIO 2.5

[doug-walker]

As discussed at the 2025-03-17 TSC meeting, we want to raise several minimum supported or recommended versions for the OCIO 2.5 release, which will become the VFX Platform release for CY2026. This issue is to pull together all of the planned work for better visibility to stakeholders and for comment from the community.

-- Raise the minimum supported language version to C++17, issue #2134
-- Update OpenImageIO recommended version to 3.x, issue #2129
-- Raise the minimum supported expat version to solve issue #2093
-- Raise the minimum supported minizip-ng version above 3.0.8 to solve issue #1818

Please let us know in the comments if you have concerns or would like to request other components be updated.

For discussion purposes, this issue is relevant: #2070.

[jfpanisset]

LCMS dependency is calling for 2.2 which is 14 years old, development has resumed and there is a 2.17 as of February 2025:

https://github.com/mm2/Little-CMS/releases/tag/lcms2.17

That would be a good candidate to update.

[doug-walker]

Adding for reference this interesting thread about Imath in #vfx_reference_platform.

[scoopxyz]

With @remia's work on this I would remove the help wanted Issues that the TSC has decided are worth implementing, but don't currently have the dev resources. label, otherwise this will be the first item seen for DevDays.

[doug-walker]

This was implemented for OCIO 2.5. There is a table in the description of PR #2192 that shows how the minimum and recommended versions have been updated.