Stabilize 'build.py'

[padix-key]

• [x] I have searched the issues of this repo and believe that this is not a duplicate.
• [x] I have searched the documentation and believe that my question is not covered.

Feature Request

In order to compile C-extensions, it is currently required to add a build script to the project directory and to pyproject.toml:

[tool.poetry]
build = "build.py"

This feature is described in #11, but not in the official Poetry documentation. So my question is whether this feature is stable. If this is the case, I would like to propose to include it in the official documentation.

[medley56]

@abn Do you have any updates on the status of the build feature? I understand not wanting to include documentation until it's ready but the community could use some guidance on how to use/test out this feature because people want to use this now, even if it's not documented and projects will likely require changes after the feature is complete.