Add Helm Refurbish approach into dev docs

[bugraoz93]

related: #64037
Add README_HELM_CHART2_DEV.md and update README_AIRFLOW3_DEV.md

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[jscheffl]

FYI @Miretpl @wolfdn

[jscheffl]

Looks good to me!

[potiuk]

LGTM. I will let others review as well @jedcunningham @Miretpl

[Miretpl]

I think that the non-trivial refactoring which is mentioned in a couple of places, can be confusing for users in terms of what is trivial refactoring and what is not. On the other hand, we want to have some grey area here, but the question is - could/should we make it a little more precise?

In general - LGTM

[bugraoz93]

I think that the non-trivial refactoring which is mentioned in a couple of places, can be confusing for users in terms of what is trivial refactoring and what is not. On the other hand, we want to have some grey area here, but the question is - could/should we make it a little more precise?

In general - LGTM

Thanks @Miretpl for your comment! I deleted non-trivial description from any kind of refactor keywords. Those shouldn't be needed in backcompat rather fixes or things should small enough to follow up.

...
## Merging PRs targeted for Airflow Helm Chart 2.X

PRs should target `main` branch.
We will cherry-pick relevant changes to `chart/v1-2x-test` branch if we decide that they are relevant to the latest release.
...

I have added this to be more precise rather the gray area is now confluence document that is already on going (connected Google Doc and Github Issue in the Confluence page) if anyone really want to dig deep and can leave comment to any of those items (Google Docs, Github issue) :) If you still this won't be enough, I can add a section to maybe explain the things can change by the time to explain the gray area better. What do you think?

[Miretpl]

@bugraoz93 looks good, thanks!

[github-actions]

Backport successfully created: v3-1-test

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
✅	v3-1-test