Add ProPhoto RGB standard #356

Job	Run time
Quick check (beta)	2m 4s
Documentation	22s
Compile and test MSRV (ubuntu-latest)	8m 57s
Quick check (stable)	1m 56s
Compile and test MSRV (macos-latest)	7m 14s
Compile and test MSRV (windows-latest)	13m 8s
Quick check (nightly)	2m 5s
integration tests (ubuntu-latest)	20s
integration tests (macos-latest)	24s
integration tests (windows-latest)	2m 45s
Miri tests	4m 16s
Test #[no_std]	23s
ci	1s
	43m 55s

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