[sdk] Rename PipelineSyncPlugin to StagePlugin (missed to rename)

[t-kikuc]

What this PR does:

as title.
some methods were not fixed yet.

Why we need it:

To be consistent

Which issue(s) this PR fixes:

Part of #5530
Follows #5587

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[khanhtc1202]

Nice catch 👍

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.

Project coverage is 26.26%. Comparing base (7b78a17) to head (69bb589).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/plugin/sdk/deployment.go	0.00%	13 Missing ⚠️
pkg/app/pipedv1/plugin/example/main.go	0.00%	1 Missing ⚠️
...app/pipedv1/plugin/kubernetes_multicluster/main.go	0.00%	1 Missing ⚠️
pkg/app/pipedv1/plugin/wait/main.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5593   +/-   ##
=======================================
  Coverage   26.26%   26.26%           
=======================================
  Files         472      472           
  Lines       50388    50388           
=======================================
  Hits        13234    13234           
  Misses      36094    36094           
  Partials     1060     1060           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ffjlabo]

👍