Poetry: install alpha builds

By default, Python package installation tools (e.g. pip, Poetry) will prefer “stable” releases over alpha, beta, dev.

For Poetry specifically, if you have a release 0.4.2a0 and are trying to install it just using ==0.4.2, Poetry will not be able to find it.

Use allow-prereleases = true to explicitly tell Poetry you want to use pre-releases.

For example:

[tool.poetry.dependencies]
my-package = {version = "^0.4.2a0", allow-prereleases = true }