move author tests to xt

diff --git a/t/author/pod-coverage.t b/xt/author/pod-coverage.t
similarity index 100%
rename from t/author/pod-coverage.t
rename to xt/author/pod-coverage.t

diff --git a/t/author/pod.t b/xt/author/pod.t
similarity index 100%
rename from t/author/pod.t
rename to xt/author/pod.t