Pep440 issue installing branch with poetry

[euri10]

While waiting for #44 to be merged I wanted to use my fork, howwever poetry finds the version = ' dev' is not pep404 compatible and refuses to install/
something like 0.4.0.dev maybe would be more appropriate ?

[samuelcolvin]

we should:

• remove poetry - use hatchling instead
• pin requirements so tests don't fail
• set the version in pyproject.toml and check it matches the release tag using https://github.com/samuelcolvin/check-python-version

Effectively copy the set up from https://github.com/samuelcolvin/pytest-pretty.

I'm pretty busy trying to get the alpha of pydantic out today and tomorrow, might be able to look on Tuesday.