Update release guide to include the step of bump etcd for K8s

[ahrtr]

cc @ivanvc @joshjms @hakman @ArkaSaha30

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[k8s-ci-robot]

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[hakman]

/lgtm

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.16%. Comparing base (91201b1) to head (3d9d151).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

see 20 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #20936      +/-   ##
==========================================
- Coverage   69.21%   69.16%   -0.06%     
==========================================
  Files         422      422              
  Lines       34839    34839              
==========================================
- Hits        24115    24095      -20     
- Misses       9326     9339      +13     
- Partials     1398     1405       +7     

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