Cut a release that includes support for keyword-only arguments

[alanfalloon]

Bazel 2.1 instroduced Starlark changes that allow keyword-only parameters.

For example:

def foo(arg1, arg2, *, kwonly1):
    pass

But running Stardoc 0.4.0 on .bzl files with that new syntax fails with:

Stardoc documentation generation failed: Starlark evaluation error

[alanfalloon]

I didn't try a version from master, but a quick skim of the commits didn't show any obvious changes to Starlark evaluation.

[brandjon]

It actually seems like a somewhat major issue to me that Stardoc would be incompatible with keyword-only arguments.

I was able to reproduce this issue with Stardoc 4.0, but it seems to be fixed at head. So I suppose the real issue is cutting a new release.