Fix: group

[fangyincheng]

What this PR does:

Which issue(s) this PR fixes:

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-io]

Codecov Report

Merging #244 into develop will increase coverage by 0.02%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop     #244      +/-   ##
===========================================
+ Coverage    64.97%   64.99%   +0.02%     
===========================================
  Files          104      104              
  Lines         6744     6745       +1     
===========================================
+ Hits          4382     4384       +2     
+ Misses        1920     1919       -1     
  Partials       442      442

Impacted Files	Coverage Δ
protocol/dubbo/client.go	69.07% <100%> (+0.2%)	⬆️
config_center/zookeeper/listener.go	86.95% <0%> (+4.34%)	⬆️

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