This reverts commit b0859c20.

With this mode zc.buildout and its dependencies are installed
from scratch directly in the local eggs directory, following
the pinned versions if any apply.

In offline mode this merely ensures that the required eggs are
already installed in the local eggs and develop-eggs directory.

[ci skip]

[skip ci]

[ci skip]

[ci skip]

[skip ci]

For example: `[versions:python_version <= "3.9"]`.
Fixes https://github.com/buildout/buildout/issues/621

[skip ci]

[skip ci]

in 3.11

Also update action/checkout version

files in subdirs were not managed

in the dev environment

Also fixed virtualenv install under 2.7