Support Stamping of version in py_wheel

[tmspicer]

🚀 feature request

Relevant Rules

Rule: py_wheel

Description

Currently the version of py_wheel is a hardcoded string that would need to be changed frequently. We would like to produce development wheel and automated version when tagging so this is not an ideal situation.

Describe the solution you'd like

I would like to propose that we add support for stamping of the version attribute so that the version can be read via the workspace_status file.

Describe alternatives you've considered

Alternatives could be to pass in a version file but then your build process has to write that. As the workspace_status mechanism is supported on multiple rules it makes more sense to add support for it.
Another option is makefile variables or macros but since we version off of git output the values are dynamic.

[jakeleventhal]

And destination!

[jakeleventhal]

Can be solved by allowing access to stable status variable resolution in strings in the py_wheel rule

[tmspicer]

PR #545 allows stamping with volatile variables

[thundergolfer]

I think this was closed by #554.

Let me know if that's not the case.