Add ci.opensearch.org maven2 mirror to avoid throttling

[gaiksaya]

Description

Add ci.opensearch.org maven2 mirror to avoid maven central throttling

Issues Resolved

opensearch-project/opensearch-build#6062

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[github-actions]

PR Code Analyzer ❗

AI-powered 'Code-Diff-Analyzer' found issues on commit 027f918.

Path	Line	Severity	Description
settings.gradle	6	high	A custom Maven repository (https://ci.opensearch.org/maven2/) is added to pluginManagement and placed FIRST in the resolution order, before gradlePluginPortal() and mavenCentral(). Gradle resolves plugins from repositories in order, so any plugin artifact present on this custom server would shadow the official version from the Gradle Plugin Portal or Maven Central. Even if ci.opensearch.org is a legitimate OpenSearch CI host, adding an unverified repository with priority override is a supply chain risk — maintainers must confirm this URL is intentional, controlled by the project, and served over a trusted, integrity-verified endpoint.

The table above displays the top 10 most important findings.

Total: 1 | Critical: 0 | High: 1 | Medium: 0 | Low: 0

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Pull Requests Author(s): Please update your Pull Request according to the report above.

Repository Maintainer(s): You can bypass diff analyzer by adding label skip-diff-analyzer after reviewing the changes carefully, then re-run failed actions. To re-enable the analyzer, remove the label, then re-run all actions.

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⚠️ Note: The Code-Diff-Analyzer helps protect against potentially harmful code patterns. Please ensure you have thoroughly reviewed the changes beforehand.

Thanks.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.53%. Comparing base (490bac2) to head (027f918).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #3345      +/-   ##
============================================
+ Coverage     83.51%   83.53%   +0.01%     
  Complexity     4304     4304              
============================================
  Files           451      451              
  Lines         15587    15587              
  Branches       2018     2018              
============================================
+ Hits          13018    13020       +2     
+ Misses         1779     1777       -2     
  Partials        790      790              

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