[release/6.0] Onboard new inter-branch merge flow [Workflow]

[f-alizada]

Context

Onboarding new merge flow based on the github actions

Changes Made

Added github workflow for the branch.

References

Documentation https://github.com/dotnet/arcade/blob/main/Documentation/Maestro/New-Inter-Branch-Merge-Approach.md
One pager: https://github.com/dotnet/dnceng/blob/main/Documentation/OnePagers/github-action-inter-branch-merge.md

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[ericstj]

Is it normal to use main in a release branch? I would expect each release branch to use the respective release branch of arcade (and ideally at a matching commit to that arcade which is ingested in the repo). @mmitche

[mmitche]

We use main in arcade for publishing and other common automation (including this automation in its current form). The scripting for inter-branch merging has changed minimally over the years and isn't release specific in any way.

[ericstj]

@f-alizada @mmitche can you help explain to us what this does. I see a lot of mention of inter-branch merges but I'm not sure what is meant by that. Can you give us an example?

[mmitche]

@ericstj This is the automation that merges between branches in GitHub (e.g. release/6.0->release/7.0 in some repos). It generates these PRs: #104330

This automation is moving from being triggered by old Maestro, to being triggered by GitHub Actions

[carlossanlop]

@mmitche so does this look good to merge?

[mmitche]

Yep good to go.