Ability to skip the installation of the package in `prep-git`

[jtpio]

Problem

Follow-up to #319 (review)

Some projects use a top-level pyproject.toml to manage configuration for Python monorepos (isort, tbump), without the top-level being installable.

For example JupyterLite: https://github.com/jupyterlite/jupyterlite/blob/main/pyproject.toml

The default installation step in prep-git is then causing some issues because the top-level is not installable:

jupyter_releaser/jupyter_releaser/lib.py

Lines 599 to 602 in 02418b2

	# Install the package
	# install python package in editable mode with dev and test deps
	if util.PYPROJECT.exists():
	util.run('pip install -q -e ".[dev,test]"')

Proposed Solution

Maybe there could be a new releaser configurable option to skip this installation step.

Or the installation step moved to another step, so it can be skip-ed

Additional context

#319 (review)

[blink1073]

Perhaps we should load the file and check for build metadata?

[jtpio]

Perhaps we should load the file and check for build metadata?

Good point, sounds like this should work 👍

[bollwyvl]

It looks like pip might actually back up some of these changes (or introduce flags), as it broke way more just flit editable installs.