Update seastar submodule
Update seastar submodule

* seastar 92c488706...c7b6b84e5 (6):
  > semaphore: Use futurize_invoke instead of futurize_apply
  > future: specify futurize::make_exception_future as noexcept
  > future: Move ignore out of line
  > future: Split then and then_impl to enable NRVO
  > semaphore_units: allow getting the number of units held
  > Merge "Split futurize::apply into invoke(...) and apply(tuple)" from Rafael

scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla