Some server on the wild are badly configured. Either by mistake or lack
of maintenance. Safe and unsafe Ciphers change overtime based on new
discoveries.
This proposition will include considered unsafe ciphers when `Allow self-signed or invalid certificates` is used.
It could be put into a separate option but, I felt this could fit in.
fix#2671
The recent HTTP client refactor in 14e25ab9fe
introduced a bug in which the global default User-Agent is no longer
used for requests. Unless a per-feed User-Agent exists, the Go standard
library's default User-Agent is used, which looks something like
"Go-http-client/1.1". To fix this, make RequestBuilder.WithUserAgent
take an additional argument, the default User-Agent, which will be used
if there is no per-feed User-Agent (i.e. it is an empty string).
Fixes#2188Fixes#2189