sysutils/pam_xdg: update to 0.8.3

fetch: https://ftp.sdaoden.eu/pam_xdg-0.8.2.tar.gz: Not Found

Changes: https://github.com/sdaoden/s-toolbox/commit/d8f24368d950
Changes: https://github.com/sdaoden/s-toolbox/commit/b5608df1550f
Reported by: upstream (via mail)

(cherry picked from commit 579335bc7d164afdd77d8a443d42d4b3b49fa32b)