📖 Add k8s README

[spencerschrock]

What kind of change does this PR introduce?

docs update explaining how to apply k8s changes to the cron job infrastructure

• PR title follows the guidelines defined in our pull request documentation

What is the current behavior?

What is the new behavior (if this is a feature change)?**

• Tests for the changes have been added (for bug fixes/features)

Which issue(s) this PR fixes

NONE

Special notes for your reviewer

Does this PR introduce a user-facing change?

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[codecov]

Codecov Report

Merging #2219 (4966088) into main (5ac9f39) will increase coverage by 2.64%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2219      +/-   ##
==========================================
+ Coverage   42.25%   44.90%   +2.64%     
==========================================
  Files          95       95              
  Lines        7977     7977              
==========================================
+ Hits         3371     3582     +211     
+ Misses       4344     4124     -220     
- Partials      262      271       +9     

[azeemshaikh38]

Thanks!

[github-actions]

Integration tests success for
[c3b9a15]
(https://github.com/ossf/scorecard/actions/runs/2958257220)

[github-actions]

Integration tests success for
[4966088]
(https://github.com/ossf/scorecard/actions/runs/2958278619)