[3.20] community/age: security upgrade to 1.2.1

"A plugin name containing a path separator may allow an attacker to execute an arbitrary binary."

• https://github.com/FiloSottile/age/security/advisories/GHSA-32gq-x56h-299c
• https://github.com/FiloSottile/age/releases/tag/v1.2.1