HTTP/2 cleartext (h2c) for container probes

[amritansh1502]

Enhancement Description

• One-line enhancement description (can be used as a release note): Support HTTP/2 cleartext (h2c) container probes so apps don’t need a separate probe port

• Kubernetes Enhancement Proposal: Add KEP-5999 for HTTP/2 cleartext (h2c) container probes #6000

• Discussion Link: Enhancement was discussed before KEP creation -
  Support HTTP2 probes over cleartext (h2c) kubernetes#125599
  In the same area but different enhancement -
  Support TLS Credentials in gRPC Probe #4939

• PRs by stage and milestone:

  • Alpha - v1.xx
    • KEP (k/enhancements) update PR(s):Add KEP-5999 for HTTP/2 cleartext (h2c) container probes #6000
    • Code (k/k) update PR(s):
    • Docs (k/website) update PR(s):

Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently.
cc: @SergeyKanzhelev @haircommander @ngopalak-redhat

[ngopalak-redhat]

/assign @amritansh1502
As discussed @amritansh1502 Will prepare a draft KEP soon.

[SergeyKanzhelev]

/sig node
/sig network
/kind kep
/stage alpha