Mention OpenColorIO as a new adoption case #1548

Job	Run time
host_x86 (x86_64, g++-10)	2m 37s
host_x86 (x86_64, clang++-11)	35s
host_win_msvc	2m 1s
host_win (x86_64)	1m 5s
host_win (armv7)	1m 15s
host_win (aarch64)	1m 7s
host_arm (armv7, none, g++-10)	4m 52s
host_arm (armv7, none, clang++-11)	5m 11s
host_arm (aarch64, none, g++-10)	4m 40s
host_arm (aarch64, none, clang++-11)	4m 30s
host_arm (aarch64, crypto+crc, g++-10)	4m 39s
host_arm (aarch64, crypto+crc, clang++-11)	5m 59s
coding_style	27s
test_win_msvc	1m 15s
	40m 13s

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