Add firmware version in the USB descriptor

[kauwua]

Could be done through a CMake template that would generate a variable based on git describe.

[bvernoux]

We could do like on hydrabus using build-scripts (bash/shell scripts) https://github.com/hydrabus/hydrafw/tree/master/src/build-scripts
If something better can be done it will be perfect

[doegox]

I'm also in favor of a script, not sure you can cover all cases easily from pure cmake.
Cases to cover are also:

• compilation from a release sources.zip => not local git info available
• compilation on environments where git was not installed, e.g. from a HEAD zip

Food for thought: the pm3 script

• we use env git to detect if git is available
• in the release zips we remove the dynamic version computation and we hardcode the version, cf Makefile#L376

[kauwua]

I've used both https://github.com/RfidResearchGroup/proxmark3/blob/master/tools/mkversion.sh and https://github.com/hydrabus/hydrafw/tree/master/src/build-scripts, there's an example of the result in the PR