- OAK_ENABLE_DYNAMIC_RENDER_BACKEND now defaults ON; it was previously
undefined (OFF) unless passed, so CI configure failed on the
unconditional oakgl target references in app/worker/tests
- add git to the MSYS2 package list in ci.yml and cd.yml; the OTIO
build step runs git clone in the msys2 shell, where git is not
installed by default