sysutils/yadm: update to 2.4.0

From ChangeLog: https://github.com/TheLocehiliosan/yadm/releases/tag/2.4.0

Update version number and update documentation

• Support multiple keys in yadm.gpg-recipient (#139)
• Ensure all templates are written atomically (#142)
• Add encrypt_with_checksums to the hooks collection (#188)
• Escape white space in YADM_HOOK_FULL_COMMAND (#187)
• Improve parsing of os-release (#194)
• Improve identification of WSL (#196)
• Fix troff warnings emitted by man page (#195)
• Write encrypt-based exclusions during decrypt

PR: 244509
Submitted by: vendion@gmail.com (maintainer)