This module sets the build number from a file.
It reads a number from a text file, increments it, and uses that as
the build number.
During the 'cleanup' stage, the new build number is written, therefore
the next build will have a build number that is 1 higher.

The default path to the file where the build number is stored is
/tmp/oob-buildnr but you can customize this in the configuration:

[buildnr_from_file]
path=/path/to/version/file