MiCall Reports should have a version number

[wrpscott]

The Resistance reports should have a version number which reflects the software version in a traceable way. Perhaps a commit hash could be used?

[wrpscott]

Perhaps something like this would work:
git describe --long --dirty --abbrev=10 --tags
This produces a string of the form 'v7.7.0-4-g5b9322c61c'

[donkirkby]

We could probably add something to the script that builds the Docker image to write a version stamp into version.txt file, then display the contents in the report.

If the script for building the Docker image is getting more complicated, we should move it from the contributing file to a script file in Git.