Update to caddy v2.9.0 stable

[Marcus1Pierce]

I checked that Caddy version 2.9.0 already has a stable version. Maybe it's possible to update the Docker version as well.

[mholt]

It takes several days for a new Docker image, and today is an international holiday, so please be patient while everyone comes back online. Plus, we might have a hotfix to first.

[sharifm-informatica]

What can we do to eliminate the complexity of creating a new docker version? How can I help?

[francislavoie]

There's not really any room for improvements in the process. It's already as streamlined as it can be.

Right now, we're waiting for 2.9.1 because of major breakages in 2.9.0 that are being solved.

[mholt]

I think we're almost ready to tag 2.9.1, I'm just waiting through today to hear back about one fix (being tested in production) and one PR that I am still wrapping up.

[francislavoie]

docker-library/official-images#18209 it'll be available soon (once the jenkins build queue finishes)