CHIA-595: Keccak256 soft-fork #1788

Job	Run time
Wheel on macos-12 py-3.8	2m 58s
Wheel on ubuntu-latest py-3.8	2m 24s
Checks	56s
Wheel on windows-latest py-3.8	3m 46s
coverage	7m 52s
Run fuzz targets (macos-12, 3.8)	20m 13s
Unit tests (macos-12, 3.8)	4m 53s
Run fuzz targets (ubuntu-latest, 3.8)	17m 5s
Unit tests (ubuntu-latest, 3.8)	3m 30s
Unit tests (windows-latest, 3.8)	6m 51s
Upload to PyPI	24s
	1h 10m 52s

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