This script supports 'get', 'put' and 'vi' commands to edit the file at
http://releases.wagtail.io/latest.txt. Usage is fairly straightforward:
$ scripts/latest.sh get my-latest.txt
$ vi my-latest.txt
$ scripts/latest.sh put my-latest.txt
Or, in a single command (equivalent to get, vi and put):
$ scripts/latest.sh vi
'put' will automatically create a CloudFront invalidation, that
typically takes around 15 minutes to fully deploy
TODO: documentation; script to create a template latest.txt based on
command-line arguments.
