🔒 Fix STARTTLS stripping vulnerability (backports #664)#666

nevans merged 3 commits into

v0.4-stableruby/net-imap:v0.4-stablefrom

backport/v0.4/STARTTLS-strippingruby/net-imap:backport/v0.4/STARTTLS-strippingCopy head branch name to clipboard