add disclaimer for generated files #920

Job	Run time
Test install with generated cython files	3m 36s
Test installation using newest version of Taskflow	3m 16s
Python 3.9	5m 3s
Python 3.9	7m 58s
Test sse2 code on Linux (gcc)	7m 3s
Test installation using system supplied libs	3m 13s
Python 3.9	5m 45s
Python 3.10	5m 3s
Python 3.10	9m 54s
Python 3.10	5m 29s
Python 3.11	5m 1s
Python 3.11	13m 12s
Python 3.11	5m 10s
Python 3.12	5m 12s
Python 3.12	12m 6s
Python 3.12	6m 42s
Python 3.13	5m 7s
Python 3.13	11m 13s
Python 3.13	7m 43s
	2h 7m 46s

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