Log Message:
p5-Digest-SHA: update to 6.02.

6.02  Fri Apr 20 16:25:30 MST 2018
	- silenced compiler warnings from VS2017
		-- ref. rt.cpan.org #124477
		-- thanks to Sergey Aleynikov for diagnostics
	- modified addfile to return error when given a directory name
		-- makes behavior consistent with GNU coreutils shaXsum
		-- thanks to Scott Baker for pointing this out