Bump version for v1.15.19 release #208

Job	Run time
Run test and build (ubuntu-24.04-arm)	1m 17s
Run test and build (macos-15-intel)	3m 31s
Run test and build (macos-14)	1m 34s
Run test and build (ubuntu-latest)	1m 39s
Run test and build (macos-15)	2m 27s
	10m 28s

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