Add release notes for v1.18.3

[willie-yao]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
This PR adds release notes for release v1.18.3

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• cherry-pick candidate

Release note:

NONE

[mboersma]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 22a7d2ed69ea0ea8dad83075e00c8c5d4f56eaa1

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.86%. Comparing base (df608bd) to head (8a734a7).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5559   +/-   ##
=======================================
  Coverage   52.86%   52.86%           
=======================================
  Files         272      272           
  Lines       29474    29474           
=======================================
  Hits        15582    15582           
  Misses      13080    13080           
  Partials      812      812           

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[nawazkh]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nawazkh

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