[submodule] update sonic-swss submodule

Including the following changes:
  [bitmap_vnet] Remove BMTOR implementation (sonic-net#1496)
  [intfsorch] Init proxy_arp variable while adding router interface. (sonic-net#1473)
  [drop counters] Clarify log messages for initial counter setup (sonic-net#1445)

Signed-off-by: Liat Grozovik <liatg@nvidia.com>