[Submodule update] sonic-util

 [201911][thermal control] Backport changes from master branch (#929)
     [201911][config] Support abbreviation (#933)
       Add 'hw-management-generate-dump.sh' to 'show techsupport'
       command (#934)
       [fwutil]: Update fwutil to v2.0.0.0. (#942)
       Fixes bug for PFCWD feature parameters (#838)
     Fixed fast-reboot for BFN platform (#871)
     [config] Add 'interface transceiver' subgroup with 'lpmode' and
     'reset' subcommands (#904)
      [warm-reboot]: added pre-check for ISSU file (#915)
       [config] Don't attempt to restart disabled services (#944)