Add release notes for 2.9.0.0

[cwperks]

Description

Add release notes for 2.9.0.0

• Category

Documentation

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[codecov]

Codecov Report

Merging #2992 (9f02a31) into main (37aacdc) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #2992   +/-   ##
=========================================
  Coverage     62.31%   62.31%           
  Complexity     3369     3369           
=========================================
  Files           267      267           
  Lines         19772    19772           
  Branches       3355     3355           
=========================================
  Hits          12321    12321           
+ Misses         5807     5806    -1     
- Partials       1644     1645    +1     

see 3 files with indirect coverage changes

[RyanL1997]

* What went wrong:
Execution failed for task ':compileTestJava'.
> Could not resolve all dependencies for configuration ':testCompileClasspath'.
   > Conflict found for the following module:
       - org.apache.logging.log4j:log4j-core between versions 2.20.0 and 2.17.1

This bwc failing is caused by the merge of: opensearch-project/OpenSearch#8307.

[cwperks]

@opensearch-project/engineering-effectiveness This PR is stuck on failing bwc checks. Its stuck because its claiming mismatching log4j versions in 2.9. Security plugin expects 2.17.1, but its complaining that its conflicting with 2.20.0 somewhere.

I see in the maven snapshots repo that it also shows 2.20.0: https://aws.oss.sonatype.org/content/repositories/snapshots/org/opensearch/opensearch/2.9.0-SNAPSHOT/opensearch-2.9.0-20230712.171946-191.pom

But buildSrc/version.properties show 2.17.1: https://github.com/opensearch-project/OpenSearch/blob/2.9/buildSrc/version.properties#L16

Why does the 2.9.0 SNAPSHOT show 2.20.0?

[cwperks]

Build 190 shows 2.17.1: https://aws.oss.sonatype.org/content/repositories/snapshots/org/opensearch/opensearch/2.9.0-SNAPSHOT/opensearch-2.9.0-20230712.163210-190.pom

Something changed in build 191

[reta]

Something changed in build 191

@cwperks I think I know what was happening: when 2.9 was cut, the 2.x version was not changed but continued to get new pull request merged (so 2.9.0-SNAPSHOTs were published from 2.x and 2.9 at the same time), including log4j 2.20.0. The 2.x was bumped to 2.10.0-SNAPSHOT a few hours ago, once the new 2.9.0-SNAPSHOT becomes available, things should get back on track.

[cwperks]

That explains it. Thank you @reta

[cwperks]

The new errors are due to a recent core refactor. Working on stabilizing the main branch now.