[sonic-utilities] Update submodule (#4770)

* src/sonic-utilities 5765570...a21e01a (13):
  > [config] Don't attempt to restart disabled services (#944)
  > [crm] Use swsssdk API instead of redis-cli for getting keys from redis DB (#943)
  > Fixed fast-reboot for BFN platform (#871)
  > [sfputil] Add support of platform.json (#767)
  > [show] Add support for SONiC Gearbox Manager via new gearboxutil utility (#931)
  > [warm-reboot]: added pre-check for ISSU file (#915)
  > Add_intf_range (#913)
  > add fec config/show option (#764)
  > Make sure db_migrator is run after all config are loaded during (#926)
  > Changes to make lldp show command for multi-npu platforms. (#914)
  > [showtech]: add knet dump information in show tech (#925)
  > Vnet alias mapping (#924)
  > Revert the change to kdump reboot (#916)