Remove class-factory from wsgischema.xml for Zope > 6.0 support

[perrinjerome]

This was also removed from the original wsgischema from Zope in zopefoundation/Zope#1290

Fixes #212

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---

If your pull request closes an open issue, include the exact text below, immediately followed by the issue number. When your pull request gets merged, then that issue will close automatically.

Closes #212

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I tested that zope starts when running uv run --with zc.buildout buildout -v && ./bin/zopeinstance fg, first with a buildout on the latest released Zope, 6.0:

## buildout from https://zope.readthedocs.io/en/latest/INSTALL.html#using-plone-recipe-zope2instance
[buildout]
extends =
    https://zopefoundation.github.io/Zope/releases/6.0/versions-prod.cfg
parts =
    zopeinstance

[zopeinstance]
recipe = plone.recipe.zope2instance
eggs =
user = admin:adminpassword
http-address = 8080
zodb-temporary-storage = off
###


## develop plone.recipe.zope2instance on this branch
[buildout]
develop =
    ../plone.recipe.zope2instance
[versions]
plone.recipe.zope2instance =

and with the next versions of ZODB and Zope:

## buildout from https://zope.readthedocs.io/en/latest/INSTALL.html#using-plone-recipe-zope2instance
[buildout]
extends =
    https://zopefoundation.github.io/Zope/releases/6.0/versions-prod.cfg
parts =
    zopeinstance

[zopeinstance]
recipe = plone.recipe.zope2instance
eggs =
user = admin:adminpassword
http-address = 8080
zodb-temporary-storage = off
###


## develop plone.recipe.zope2instance on this branch and Zope on current master branch
[buildout]
develop =
    ../plone.recipe.zope2instance
    ../Zope
[versions]
plone.recipe.zope2instance =
Zope =

## next ZODB version
[versions]
ZODB = 6.3

and zope starts in both cases

[dataflake]

Looks like it was never documented or used within the context of plone.recipe.zope2instance, anyway.

[perrinjerome]

Yes and also before the recent changes in Zope/ZODB, this configuration was not working, setting it had no effect.

Thanks

[dataflake]

@perrinjerome This would be a good time for a release. I can't make a new Zope release before plone.recipe.zope2instance is released with this change.

[perrinjerome]

@dataflake I agree that it's a good time for a release, but I don't know who can make one.

[dataflake]

@mauritsvanrees Help 😉

[mauritsvanrees]

I have released plone.recipe.zope2instance 9.0.0a2 to PyPI (give it a few minutes).

I should have made a final release probably. But that will happen within a few weeks I expect.

[dataflake]

Hoping for a quick release. I am getting complaints that a simple "pip install zope" breaks because it pulls in Zope 6.0 and the incompatible ZODB 6.3. A new Zope release will fix it, but that will break with the current plone.recipe.zope2instance.

[mauritsvanrees]

Fair point. I have released 9.0.0 final.

[dataflake]

Thank you! I'll roll a new Zope release tomorrow morning then.

[dataflake]

Zope 6.1 is released and announced.