Update Digest::MD5 to CPAN version 2.57

Update Digest::MD5 to CPAN version 2.57

[DELTA]

2.58 Mon Oct 5 2020
- Update repo location.
- Update recent changelog entries. Let's see if that's enough to make metacpan happy.

2.57 Mon Oct 5 2020
- Merge change submitted to blead

2.56 Mon Oct 5 2020
- Github CI Perl 5.6..5.32
- Fixup MANIFEST/MANIFEST.SKIP/.gitignore
- Enable strict and warnings on all code. Drop vars.pm
- Preserve OPTIMIZE in hints/irix_6.pl
- Don't return context buffer if there isn't one.
- Silence possible loss of data warnings on Win32.