Log Message:
openimageio: updated to 2.2.20.0

Release 2.2.20 (1 Feb 2022) -- compared to 2.2.19

Fix some address sanitizer failures.
Build/CI: Deal with OpenColor renaming its master branch to main.
Windows: Fix error when compiling with MSVC.
Fix excessive memory usage when saving EXR with many channels.
TIFF: now works for 16-bit palette images.
Fix ImageBuf::read bug for images of mixed per-channel data types.

Release 2.2.19 (1 Nov 2021) -- compared to 2.2.18

Better catching of exceptions thrown by OCIO 1.x if it encounters 2.0 config files.
Address new warnings revealed by clang 13.
Fixed some minor python binding bugs.
Fix when building with Clang on big-endian architectures.
Fix occasional build breaks related to OpenCV headers.
Improvements to NetBSD and OpenBSD support..
Fixes to work with the libraw 202110 snapshot.

Release 2.2.18 (1 Sep 2021) -- compared to 2.2.17

Honor env variable CUE_THREADS (used by OpenCue) to set the default size of \ 
OIIO's thread pool.
Compatibility with OpenColorIO 2.1.
Dev: Extend Sysutil::getenv() to take a default if the environment variable is \ 
not found.

Release 2.2.17 (1 Aug 2021) -- compared to 2.2.16

Output to DPX files now supports IOProxy. (Input already did.)
typedesc.h: TypeDesc can now describe 2D and 3D bounding boxes, as arrays of 2 \ 
VEC2 aggregates (for 2D) or VEC3 aggregates (for 3D) with "BOX" \ 
semantic. The shorthand for these are TypeBox2, TypeBox3 (for float), and \ 
TypeBox2i and TypeBox3i for integer or pixel coordinte boxes.
Build: Fixes for building against fmt 8.0.0.
Build: Finding boost is more flexible when desiring static libraries.