Update MacPorts to support OCIO v2

[JGoldstone]

The listed contact for OCIO (as per 'port info opencolorio) is @MarcusCalhoun-Lopez. The listed contact email address (from 'port info opencolorio') is [email protected]. He made 406 commits last year, according to GitHub, but they were clustered towards the front of the year.

Note that he is also listed as a Homebrew maintainer, so #1311 might also benefit from reaching out.

Also note that I unfamiliar with the particulars of our build process, unit testing, and cmake, so I would really not be a good person to perform outreach here.