OpenImageIO v2.4.4.0-RC2

Changes since RC1:

• ImageCache/TextureSystem both have added a getattributetype()
  method, which retrieves just the type of a named attribute. #3559
  (2.4.4.0) NOTE: THIS IS AN ABI BREAKING CHANGE
• Python: Fix the ability to getattribute() of int64 and uint64
  metadata or attributes. #3555 (2.4.4.0)
• Build: Improvements to the generated cmake config files when
  building static libraries. #3552 #3557 (2.4.4.0)
• Support for gcc 12.1. #3480 (2.4.2.1) #3551 (2.4.4.0)
• Support building with clang 15.0. #3563 (2.4.4.0)
• Fix cross-compiling on Android failing due to -latomic check. #3560
  (2.4.4.0)
• Fix building on iOS. #3562 (2.4.4.0)