webhook server use TLS 1.2 as minimum version

[kishorj]

Issue

Fixes #2368

Description

Use TLS 1.2 as the min version for the webhook server.

Tests

Verified the webhook server refuses to negotiate TLS protocols older than 1.2.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the docs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[M00nF1sh]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kishorj, M00nF1sh

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• OWNERS [M00nF1sh,kishorj]

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[codecov-commenter]

Codecov Report

Merging #2394 (12fc830) into main (f25c48f) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #2394      +/-   ##
==========================================
- Coverage   54.03%   54.02%   -0.01%     
==========================================
  Files         138      138              
  Lines        7841     7842       +1     
==========================================
  Hits         4237     4237              
- Misses       3287     3288       +1     
  Partials      317      317              

Impacted Files	Coverage Δ
pkg/config/runtime_config.go	0.00% <0.00%> (ø)

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