Fix documentation for release-checklist

I still need to figure out the awsconfig problems.

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)
Git 2.0 is still pretty recent - why not do something more like this?
```bash
git fetch --tags
LAST_VERSION=$(git tag -l | grep -E 'v[0-9\.]+$' | sort -rV | head -1)
```