Bump net-imap to v0.4.21 for Ruby 3.3 (CVE-2025-43857)
v0.4.20 addresses CVE-2025-43857 (GHSA-j3g3-5qv5-52mj).
v0.4.21 fixes bugs in Net::IMAP::SequenceSet.
Net::IMAP::SequenceSet
Bump net-imap to v0.4.21 for Ruby 3.3 (CVE-2025-43857)
v0.4.20 addresses CVE-2025-43857 (GHSA-j3g3-5qv5-52mj).
v0.4.21 fixes bugs in
Net::IMAP::SequenceSet
.