feat: add SearchCustomization metadata support

[scolladon]

Explain your changes

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Add SearchCustomization metadata definition for v61+

Does this close any currently open issues?

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closes #920

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (bdf170a) to head (3c9b029).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #921   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           40        40           
  Lines         1083      1083           
  Branches       115       115           
=========================================
  Hits          1083      1083           

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[codeclimate]

Code Climate has analyzed commit 3c9b029 and detected 0 issues on this pull request.

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[github-actions]

Shipped in release v5.45.0.
You can install the new version using the version number or the latest-rc channel

$ sfdx plugins:install sfdx-git-delta@latest-rc
$ sfdx plugins:install sfdx-git-delta@v5.45.0

Happy incremental deployment!