Bump 2.x to 2.8.0

[bowenlan-amzn]

Description

This change is to accommodate security plugin change opensearch-project/security#2784

Issues Resolved

[List any issues this PR will resolve]

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #443 (694c26d) into 2.x (ee582e9) will not change coverage.
The diff coverage is n/a.

❗ Current head 694c26d differs from pull request most recent head 5aded87. Consider uploading reports for the commit 5aded87 to get more accurate results

@@            Coverage Diff            @@
##                2.x     #443   +/-   ##
=========================================
  Coverage     28.18%   28.18%           
  Complexity      895      895           
=========================================
  Files           231      231           
  Lines          9339     9339           
  Branches       1075     1075           
=========================================
  Hits           2632     2632           
  Misses         6470     6470           
  Partials        237      237           

[AWSHurneyt]

Closing in favor of #441