test: add unit-test for apis/opts/portbindings.go

[yuannauy123]

Ⅰ. Describe what this PR did

add test cases for portbindings #1905

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how you did it

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[pouchrobot]

@yuannauy123 Thanks for your contribution. 🍻
Please sign off in each of your commits.

[CLAassistant]

All committers have signed the CLA.

[pouchrobot]

We found this is your first time to contribute to Pouch, @yuannauy123
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[codecov-io]

Codecov Report

Merging #1951 into master will increase coverage by 0.09%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #1951      +/-   ##
=========================================
+ Coverage   63.31%   63.4%   +0.09%     
=========================================
  Files         200     200              
  Lines       15522   15522              
=========================================
+ Hits         9828    9842      +14     
+ Misses       4455    4437      -18     
- Partials     1239    1243       +4

Flag	Coverage Δ
#criv1alpha1test	33.81% <ø> (-0.05%)	⬇️
#criv1alpha2test	34.31% <ø> (+0.03%)	⬆️
#integrationtest	38.39% <ø> (-0.04%)	⬇️
#unittest	20.99% <ø> (+0.13%)	⬆️

Impacted Files	Coverage Δ
cri/v1alpha2/cri.go	66.31% <0%> (-0.18%)	⬇️
daemon/mgr/container.go	53.85% <0%> (-0.16%)	⬇️
apis/opts/portbindings.go	80.95% <0%> (+80.95%)	⬆️

[allencloud]

LGTM