The `apache/thrift` recently released a new version of `0.11.0`
several days ago. This release is compatible with other packages
and as such, there is no need to pinning the `apache/thrift`
to `master` anymore in Gopkg.toml.
This fix removes the pinning of `apache/thrift` in Gopkg.toml,
and updates all dependencies of coredns.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
prometheus.Handler is deprecated according to the godoc for the package so
instead we're using promhttp.
Additionally, we are exposing the Registry that metrics is using so other
plugins that are not inside of coredns can read the registry. Otherwise, if
we kept using the Default one, there's no way to access that from outside
of the coredns repo since it is vendored.
