[FEATURE] Automatically update shipwright installation commands upon release in README

[kaizakin]

Is there an existing feature request for this?

• I have searched the existing feature requests

Is your feature request related to a problem or use-case? Please describe.

When a new release is triggered, release builds only open PRs for readme updates into the release-... branch
this leads to a maintainer cherry-pick commits to main.

Describe the solution that you would like.

the solution for this is to create an automation
which either

• opens a PR to main
  or
• pushes the commits directly to main

Describe alternatives you have considered.

No response

Anything else?

No response