Use a forked WWW-AdventCalendar to use rssmode branch

[oalders]

Closes #211

[briandfoy]

Looks good to me

[oalders]

The blocker right now is that the build is broken using this fork:

processing article for 2011-12-01...
Strings with code points over 0xFF may not be mapped into in-memory file handles
error opening string for reading: Invalid argument at /usr/local/lib/perl5/site_perl/5.3[6](https://github.com/perladvent/Perl-Advent/actions/runs/3580313654/jobs/6022334189#step:8:7).0/Mixin/Linewise/Readers.pm line 139.

https://github.com/perladvent/Perl-Advent/actions/runs/3580313654/jobs/6022334189

[briandfoy]

In these cases, I stop using the GitHub Actions (i.e. checkout) and just do it myself as bash. If the Action doesn't cause problems, fine, but when it does, I quickly abandon it.

[oalders]

In these cases, I stop using the GitHub Actions (i.e. checkout) and just do it myself as bash. If the Action doesn't cause problems, fine, but when it does, I quickly abandon it.

Great idea and thanks for reminding me about this. I rebased and it looks like we are actually cloning the submodules the old fashioned way now.

[briandfoy]

This looks good to me.