Switch Anbox Cloud appliance to Juju 2.9

[morphis]

We do not support 2.8 anymore and the user must run 2.9

[luis4a0]

Hey @morphis, thanks! I'm OK with approving this, but please let us check first why CI is failing on MacOS 12.

[ricab]

It looks like the cloud-init timed out. I wonder if the runner is starved of resources... let's try again.

[ricab]

OK, this is passing in most setups and timing out on a specific job. We know that unfortunately our CI infrastructure is lacking in resources ATM, and that is by far the most likely explanation, so we just have to merge manually.

[ricab]

Well, I'll just try to bors one more time.

bors r+

[bors[bot]]

Build failed:

• Bors

[morphis]

thanks all!