added transpose stub to match new capability in oops (#1107)

* added transpose

* Update src/soca/State/State.h

* addressing PR suggestions

---------

Co-authored-by: Yannick Trémolet <30638944+ytremolet@users.noreply.github.com>
Co-authored-by: Francois Hebert <hebert@ucar.edu>
Co-authored-by: Travis Sluka <tsluka@ucar.edu>

src/soca/State/State.h

@@ -57,6 +57,10 @@ namespace soca {
       State(const State &);
       virtual ~State();
       State & operator=(const State &);
+      void transpose(const State & /*DistState*/, const eckit::mpi::Comm & /*global*/,
+         const int /*ensNum*/, const int /*transNum*/) {
+         throw eckit::NotImplemented("Soca State::transpose not implemented", Here());
+      }
 
       /// Rotations
       void rotate2north(const oops::Variables &, const oops::Variables &);