Automatically extract/update the version of ROHD that generates things

[mkorbel1]

Motivation

It would be nice if the generated outputs (e.g. SystemVerilog, waveform dumps) had a guaranteed accurate version number of ROHD that generated them. A version number (from pubspec.yaml) would be good, but even better would be to also include a git hash, so it can be determined exactly what generated the code.

Desired solution

Find a reliable way to figure out git hash, release information, version number, etc. and inject it into generated code.

Alternatives considered

Currently information is either omitted or manually updated (error prone).