bug#31216: commit 217b8c2e0 produces 'Can't locate Date/Parse.pm in @INC Error' perl error

[Mark H Weaver]

I've now pushed another commit b5178b325409b1eaf953f8f3007a180cbd27b167
to master, which changes the replacement perl to think it is version
5.26.1, although it's actually version 5.26.2.  With this fix, I'm now
able to build guix without 'po4a' reporting errors.

Please try it out and let me know if there are still problems.

      Mark