In CI, use newer v4 for action "upload-artifact" because v3 will be d… #483

Job	Run time
squeak.cog.spur for linux64x64	2m 22s
squeak.cog.spur for linux64x64 (DEBUG)	1m 42s
squeak.cog.spur for linux64x64 (ASSERT)	1m 51s
squeak.cog.spur (itimer) for linux64x64	1m 56s
squeak.cog.spur (itimer) for linux64x64 (DEBUG)	1m 23s
squeak.cog.spur (itimer) for linux64x64 (ASSERT)	1m 55s
squeak.cog.spur for linux32x86	1m 22s
squeak.cog.spur for linux32x86 (DEBUG)	2m 21s
squeak.cog.spur for linux32x86 (ASSERT)	2m 23s
squeak.cog.spur (itimer) for linux32x86	2m 53s
squeak.cog.spur (itimer) for linux32x86 (DEBUG)	2m 51s
squeak.cog.spur (itimer) for linux32x86 (ASSERT)	2m 43s
squeak.sista.spur for linux32x86	3m 29s
squeak.stack.spur for linux64x64	1m 51s
squeak.stack.spur for linux32x86	2m 55s
	33m 57s

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