Docker: Update build image with final OCIOv2, Qt 5.15.2, OTIO, Crashpad (#1489)

* Add missing xcb-util-* packages. Qt's libqxcb.so seems to require them in the newer Qt version

* Adjust breakpad install prefix to match CMake change

* Add build script for Olive for quick testing

* .n in CI image actually stands for image revision

* skipping the CI is now supported natively by GitHub Actions

docker/scripts/build_ocio.sh

@@ -7,7 +7,7 @@ set -ex
 mkdir ocio
 cd ocio
 
-git clone --depth 1 https://github.com/AcademySoftwareFoundation/OpenColorIO.git
+git clone --depth 1 --branch "${OCIO_VERSION}" https://github.com/AcademySoftwareFoundation/OpenColorIO.git
 cd OpenColorIO
 
 mkdir build