Update to v0.2 control container by default

[tjkirch]

This is to get #405.

Testing done:

Launched with this change as user data, confirmed it got the new container:

$ aws ssm start-session --target i-01739b31f4f65d2cb

Starting session with SessionId: tjk-059240cd729ac0535
Welcome to Thar's control container!
...SNIP...
To enable the admin container, run:

   enable-admin-container

[ssm-user@ip-192-168-126-46 /]$ enable-admin-container 
Checking whether there are pending settings; we don't want to silently commit other changes
...SNIP...
The admin container is now enabled - it should pull and start soon, and then you can SSH in

[tjkirch]

(oops; fixed commit/PR title to "0.2")