www/angie-module-cache-purge: Update 2.5.5 => 2.5.6
Changelog:
https://github.com/nginx-modules/ngx_cache_purge/releases/tag/2.5.6
PR: 294178
Sponsored by: UNIS Labs
MFH: 2026Q1
(cherry picked from commit 5384506eae6eb0f94bf6af6ad766ebeca4babe8a)