Port 8076 update GitHub actions for k8s slack and more

[phalbert]

Description

Update Github actions for K8s, Slack and More

Updated docs pages

Please also include the path for the updated docs

• docs/create-self-service-experiences/setup-backend/github-workflow/examples/kubernetes/manage-clusters.md
• docs/create-self-service-experiences/setup-backend/github-workflow/examples/promote-to-production.md
• docs/create-self-service-experiences/setup-backend/github-workflow/examples/broadcast-api-consumers-message.md
• docs/create-self-service-experiences/setup-backend/github-workflow/examples/manage-pull-requests.md
• docs/create-self-service-experiences/setup-backend/github-workflow/examples/nudge-pr-reviewers.md
• docs/create-self-service-experiences/setup-backend/github-workflow/examples/open-slack-channel.md

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[phalbert]

go over @pazhersh comments

I have gone over them now, and updated the PR