[AUTO] [2.x] Add bwc version 2.8.1.

[opensearch-trigger-bot]

I've noticed that a new tag 2.8.0 was pushed, and added a bwc version 2.8.1.

[codecov]

Codecov Report

Merging #7938 (9054f53) into 2.x (a277cd0) will decrease coverage by 0.09%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##                2.x    #7938      +/-   ##
============================================
- Coverage     70.64%   70.55%   -0.09%     
+ Complexity    56517    56412     -105     
============================================
  Files          4671     4671              
  Lines        267858   267859       +1     
  Branches      39644    39644              
============================================
- Hits         189232   189001     -231     
- Misses        62357    62551     +194     
- Partials      16269    16307      +38     

Impacted Files	Coverage Δ
server/src/main/java/org/opensearch/Version.java	84.05% <100.00%> (+0.06%)	⬆️

... and 459 files with indirect coverage changes

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/16952/
• CommitID: 9054f53
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.index.ShardIndexingPressureSettingsIT.testShardIndexingPressureLastSuccessfulSettingsUpdate

• URL: https://build.ci.opensearch.org/job/gradle-check/16963/
• CommitID: 9054f53
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.