[v2] Prompt before auto-updating

[DrizzlyOwl]

I went to run dalmatian aws-sso and instead I got taken through an automated update process which included running brew update + terraform init and got me rather confused for a few minutes until it told me right at the end that an update was completed.

I think the user experience could be improved. We ought to make it more obvious to the user when an update is available and what it will do before proceeding. We may also decide to make it a deferrable option, (i.e. expect user confirmation before updating)

[Stretch96]

I'd made the decision to force an update when it is available, because an update could potentially include a terraform module update - which could include infrastructure changes

Ensuring that everyone is running the same (latest) version, mitigates the possibility of infrastructure accidentally being destroyed or reverted (eg. If I deploy an infrastructure using the latest, and then someone else deploys the infrastructure whilst not on the latest version)

It does prompt to say what is happening, eg:

Checking for newer version ...
The last update did not complete successfully. Attempting another update ...
Updating ...

I think it may seem weird the first time it does it - May just be something that should be expected?