Add missing search_pipeline field in opensearchapi.SearchParams

[jackh-ncl]

Description

Added search_pipeline field in SearchParams struct.

Note: I didn't add any tests as I can't see any others there for existing SearchParam fields.

Context:

With the addition of hybrid search and search pipelines in Opensearch version 2.11, a new search_pipeline parameter exists on the _search endpoint (docs here).

Issues Resolved

This pull request supports the new search pipelines functionality by allowing users of the library to set the search_pipeline parameter via the SearchParams struct.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.93%. Comparing base (06a6dc8) to head (cf059ca).
Report is 15 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #532       +/-   ##
===========================================
+ Coverage   57.29%   67.93%   +10.64%     
===========================================
  Files         315      376       +61     
  Lines        9823     8852      -971     
===========================================
+ Hits         5628     6014      +386     
+ Misses       2902     1556     -1346     
+ Partials     1293     1282       -11     

Flag	Coverage Δ
integration	60.36% <0.00%> (+9.52%)	⬆️
unit	15.26% <100.00%> (+2.42%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
opensearchapi/api_search-params.go	89.42% <100.00%> (+82.08%)	⬆️

... and 270 files with indirect coverage changes

[dblock]

We do need tests for existing and new code, can you please add something simple that exercises params, please?

[jackh-ncl]

@dblock I have pushed up some simple tests, though it's proving a bit difficult to get it right as the get() method is unexported, and golanglint wants test files to be under a test package (e.g. opensearchapi_test), which means I'm unable to access it.

I can either add make get() exported, add a nolint or it looks like I could follow this sort of structure, though I'm not too familiar with this approach.

Would appreciate any suggestions 😃

[dblock]

LGTM, @Jakob3xD has a good answer to your question?

[Jakob3xD]

LGTM, only thing missing is the build tag for testing.
Afterwards it is good to merge.

[jackh-ncl]

Thank you 😃