[New perl version] v5.42.1

[github-actions]

https://github.com/Perl/perl5/releases/tag/v5.42.1

[dscho]

As I mentioned in another ticket, I just verified that Git SVN works in a vanilla MSYS2 with our newly-upstreamed packages. Which means that the main reason why Git for Windows has its own Perl and its own subversion packages is actually no longer relevant. Vanilla MSYS2 brings all the packages that we need for git svn to work. So my current plan is to actually drop shadowing the Perl package in Git for Windows, along with subversion and the perl-* packages that Git for Windows currently builds.