security/doas: update to 6.3p12

6.3p11:
* Cleaned up error checking for temporary files, removed redundant check.
* Fixed status check for copy and editor launch.

6.3p12:
* Make sure doasedit can work when target file to edit has a leading slash
character. ie A full path name is used.
* Update doas.1 manual page to indicate problems with piping input
on Linux when processes are launched by doas.

Upstream release announcement:
https://github.com/slicer69/doas/releases/tag/6.3p11
https://github.com/slicer69/doas/releases/tag/6.3p12

PR:	278897
MFH:	2024Q2