Replaces version placeholder strings (e.g. @VERSION@) in files in a repo with the actual version.
Script is called without arguments from the root of the repo.
It requires that a config file named update_versions.conf be present at the root of the repo. This
file determines how the replacement process happens.
See update_versions.conf.template for details on this.
Displays the replacements as they happen, showing the diffs for all altered files.
Exits 0 on success, 1 otherwise.