Bug: ADC label-selector failed to synchronize according to exact matching.

[LiteSun]

Current Behavior

ADC version: 0.24.2
When the label for a service in the ADC configuration file is set to appname:yanglao_wx_pgm, using the ADC command to update only this service:
./adc sync -f service.yaml --label-selector name=yanglao_wx_pgm --include-resource-type service
will still update this service and add an extra label name:yanglao_wx_pgm.

Exxpected Behavior

1. The label filter should use precise matching; if the name:yanglao_wx_pgm label is not present, this service should not be updated.

Steps to Reproduce

Reference Current Behavior

Environment

• APISIX version:
• ADC version (run adc version): ADC version: 0.24.2
• Operating system (run uname -a):

[LiteSun]

closed by #418 (comment)