[ANNOUNCEMENT] Kubernetes provider incompatibilities with Airflow 2.1 and 2.2

[Jarek Potiuk <ja...@potiuk.com>]

Hello everyone,

TL:DR: If you used the "cncf.kubernetes" provider and you manually
installed its version above 3.0.0 -  please downgrade it to 3.0.0.

We have been made aware of some incompatibility between Airflow
2.1/2.2, and few latest cncf.kubernetes providers (3.0.1, 3.0.2,
3.1.0, 3.1.1, 3.1.2) when you upgraded the kubernetes library to a
newer version (> =12.0.0).

Unfortunately the way our extras work, the limits we put on airflow
and providers together could lead to upgrading the kubernetes library
while updating manually to the latest cncf.kubernetes provider.

This is because Kubernetes is partially in the provider and partially
in the Airflow core and it is impossible to define an optional
dependency which has some "hard" limits. We had a growing number of
reports showing the problem (from users who were eager to upgrade to
the latest provider) so we decided to take some preventive actions.

* We have "yanked" all the "cncf.kubernetes" above 3.0.0. This is the
last release that had the "hard" limit on kubernetes library, so you
should never upgrade kubernetes library to >=12 with this version.
"Yanking" means that you should only be able to install 3.0.0
automatically. You still should be able to install a specific version
by `==3.1.2` for example, but it should be skipped on automated
upgrades.

* The 2.2.4 image had cncf.kubernetes 3.0.2 version installed. This is
actually fine, because the kubernetes library installed in the 2.2.4
image still has kubernetes library < 12.0.0.

* The upcoming 2.2.5 release will use cncf.kubernetes provider version 3.0.0

* Unless we see some serious bug to fix - all the future releases of
"cncf.kubernetes" provider will only be installable for Airflow 2.3.0,
which means that it will not get updated for 2.1 and 2.2 and if you
will want to use new features from cncf,kubernetes, you will have to
upgrade Airflow to 2.3.0 (coming soon as well).

* We implemented changes in our dependency process
https://github.com/apache/airflow/pull/22573 to avoid similar problems
in the future.

Thanks for your understanding and apologies for any problems it caused.

J.