Use Selfupdate Commands Or Always Get Latest Version

[sprankhub]

What do you think of adding the following selfupdate commands to the setup.sh after the git clone?

${BUILDENV}/tools/n98-magerun.phar self-update
${BUILDENV}/tools/composer self-update

Another idea would be to always download the latest version and not keeping it in the repo at all...

[bastianccm]

self-update can fail, which is bad for CI.
Rather have a pinned tool here, which you can also use while working offline, github down, etc. etc.

[sprankhub]

Not sure if this is a valid concern since the setup is based on composer, which can also easily fail...