Temper.Push.HTTPClient over OTP's :httpc, so Temper needs no HTTP
dependency.
TLS is verified: the peer certificate against the system's CA store
(:public_key.cacerts_get/0, OTP 25+) and the host name against the
certificate. :inets and :ssl are Temper's extra applications, so
they are on the code path; they are started here as well, since a mix
task does not start the application.