Update MAINTAINERS and CODEOWNERS

[zhichao-aws]

Description

Update MAINTAINERS and CODEOWNERS

Issues Resolved

[List any issues this PR will resolve]

Check List

• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (9683d86) 66.93% compared to head (647b761) 66.93%.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #833   +/-   ##
=========================================
  Coverage     66.93%   66.93%           
  Complexity      267      267           
=========================================
  Files            39       39           
  Lines          1742     1742           
  Branches        165      165           
=========================================
  Hits           1166     1166           
  Misses          453      453           
  Partials        123      123           

Flag	Coverage Δ
opensearch-notifications	66.93% <ø> (ø)

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