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.

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

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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

* Make compatible with pip 22.2+, restoring Requires-Python functionality there.

Fixes https://github.com/buildout/buildout/issues/613.

Note: we are patching `process_url` from `setuptools`.
The existing comment says that this method was copied over from setuptools 46.1.3.
I was wondering, so I checked: the method is still the same in latest setuptools.  And it is largely unchanged since setuptools 42.0.2.
So for that part we should still be compatible with quite a long range of setuptools versions.

* process_url patch: must pass cache_link_parsing=False.

This fixes test failures: extdemo-1.5 was not found, because the previous index page containing only extdemo-1.4 was cached.
We were passing this before to HTMLPage, and still do as a fallback, but I missed that this was also needed in pip 22.2+ for the new IndexContent class.

Add support for python311-315 in conditional section expressions. [master]