security/rubygem-ed25519: update to 1.4.0

Required for gitlab 18.0

Changes: https://github.com/RubyCrypto/ed25519/blob/main/CHANGES.md
PR: 286874
Approved by: sunpoet (maintainer)

(cherry picked from commit 5b6744a7045179ffb1f875e890580f2f2059c723)