[swss] Update submodule for sonic-swss (#9314)

c31a362 - 2021-11-18 : [202012][Mux orch] set default as standby, change mux orch priority (#2015) [Prince Sunny]
9a9e8e6 - 2021-11-18 : [202012] Check VS test failure (#2033) [Prince Sunny]
7eaabca - 2021-11-11 : [202012] Fix random failure in PR/CI build. (#2016) [Shilong Liu]
85230fe - 2021-11-04 : [orchagent] Fix group name of port-buffer-drop in flexcounterorch.cpp (#1967) [Junchao-Mellanox]
a55c2ca - 2021-11-03 : [teammgrd]: Handle LAGs cleanup gracefully on Warm/Fast reboot. (#1934) [Nazarii Hnydyn]