Update seastar submodule
Update seastar submodule

* seastar 06a8c8f6e...36e8dfc89 (1):
  > reactor: decouple idle cpu handler from reactor

Ref #1.

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