We're moving from using terminology related to terminals when
we refer to Websockets connections in Workhorse.
It's more appropiate a concept like channel.
Workhorse was not able to parse the `headers` property since it was expecting a
key => array as a structure.
Error from workhorse: preAuthorizeHandler: decode authorization response: json:
cannot unmarshal string into Go struct field TerminalSettings.Header of type
[]string
Workhorse was not changed since this api is already used for the environment
terminals.
gitlab-org/gitlab-ce#25990