Update docs to mark Pluggy interface as stable rather than experimental

[TheCodyRich]

What do you see as an issue?

Pluggy interface has been listed as experimental since Airflow 2.6. Requesting it be listed as stable

Solving the problem

Change the documentation to say it is now stable

Anything else

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[jedcunningham]

Yep, I think it's time to mark it stable! Let's add a newsfragment while we are at it.

[DjVinnii]

Is this also relevant for the Listeners or is that a separate topic? As these are also using Pluggy.

[TheCodyRich]

I would assume they would be the same, but for now I've opened a PR just for the Cluster Policies