Bump version to 4.15.0 #800

Job	Run time
build-devcontainer	9m 42s
dotnet-build (Debug, ubuntu-latest)	3m 15s
fable-npm-build (ubuntu-latest, 18)	2m 10s
dotnet-build (Debug, windows-latest)	6m 34s
fable-npm-build (ubuntu-latest, 20)	2m 4s
dotnet-build (Debug, macOS-latest)	6m 10s
fable-npm-build (ubuntu-latest, latest)	2m 12s
dotnet-build (Release, ubuntu-latest)	3m 16s
fable-npm-build (windows-latest, 18)	8m 30s
fable-python-build (ubuntu-latest, 3.10)	1m 38s
dotnet-build (Release, windows-latest)	4m 52s
fable-npm-build (windows-latest, 20)	5m 53s
fable-python-build (ubuntu-latest, 3.11)	2m 46s
dotnet-build (Release, macOS-latest)	5m 25s
fable-npm-build (windows-latest, latest)	6m 31s
fable-python-build (ubuntu-latest, 3.12)	2m 56s
fable-npm-build (macOS-latest, 18)	3m 44s
fable-python-build (windows-latest, 3.10)	7m 33s
fable-npm-build (macOS-latest, 20)	3m 35s
fable-python-build (windows-latest, 3.11)	6m 23s
fable-npm-build (macOS-latest, latest)	3m 54s
fable-python-build (windows-latest, 3.12)	6m 30s
fable-python-build (macOS-latest, 3.10)	5m 2s
fable-python-build (macOS-latest, 3.11)	4m 17s
fable-python-build (macOS-latest, 3.12)	5m 18s
	2h 0m 10s

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