ci/deps: add Plack::Test::ExternalServer for devtest

More of our Plack tests exercise public-inbox-httpd, nowadays;
and ExternalServer lets us test it easily alongside generic PSGI
stuff.

diff --git a/ci/deps.perl b/ci/deps.perl
index 77d95fc8e749071237ea03dec9ff438950393f00..4c27333739bcc50a01b7b81380210b31d0ff08a5 100755 (executable)
--- a/ci/deps.perl
+++ b/ci/deps.perl
@@ -48,6 +48,7 @@ my $profiles = {
                XML::TreePP
                curl
                w3m
+               Plack::Test::ExternalServer
                ) ],
 };