For testing that we can update from the newly built version of Compass we'll just update it to something we control and can easily test.

ie. something that will just print "Update succeeded" or similar.

We need it to be a binary rather than a shell script so it will work on windows too. In the past to get around this we've used go. See signtool.go and positional-args.go for inspiration.

(We can probably just commit the built binary so we don't have to rebuild it every time?)

ALTERNATIVELY since CI is running in cygwin we might be able to get away with a shell script. Look into that first