[FEATURE] Support search_pipeline query parameter for search API requests

[devonterr]

Is your feature request related to a problem?

The Search API supports specifying a search pipeline as a query parameter in search requests. Currently there is no way to specify this parameter through this client.

What solution would you like?

Add a new parameter to the SearchRequest structure and add this as a query parameter during URL construction.

What alternatives have you considered?

Not using this client for cases which require specifying a search pipeline.

Do you have any additional context?

Planning to put up a PR momentarily!

[devonterr]

Apologies, I didn't see that this was recently added in the 4.0 changes.