Wrong certifcates on https://dl-3.alpinelinux.org/
Similar issue to this one - https://bugs.alpinelinux.org/issues/4982
Certificates currently on https://dl-3.alpinelinux.org/ are registered for default.ssl.fastly.net instead of dl-3.aplinelinux.org.
(from redmine: issue id 10470, created on 2019-05-20, closed on 2019-06-19)