mbsync: fix ssl version
mbsync: fix ssl version

Seems like isync/mbsync still use TLS 1.0 by default because it "confuses
some servers". Seems like that's a reason to configure a lower version,
not to make it the default. Anyway, until the Debian patch in #871813 is
included, this is strictly necessary.

paretje/dotfiles,paretje/dotfiles,paretje/dotfiles,paretje/dotfiles,paretje/dotfiles