use GHCR images instead of Docker images

conf.py

@@ -1,10 +1,6 @@
-import sys
 import time
 
-sys.path.insert(0, '_extensions')
-
 extensions = [
-    'ubuntu_version',
     'notfound.extension',
     'sphinx.ext.extlinks',
     'sphinx.ext.intersphinx',
@@ -203,7 +199,3 @@
 copybutton_prompt_text = "$ "
 # https://sphinx-copybutton.readthedocs.io/en/latest/use.html#honor-line-continuation-characters-when-copying-multline-snippets
 copybutton_line_continuation_character = "\\"
-
-# Must be synchronized with the Ubuntu image version in
-# https://github.com/python/cpython/blob/main/Tools/build/regen-configure.sh
-configure_ubuntu_version = "22.04"

developer-workflow/extension-modules.rst

@@ -593,34 +593,14 @@ by executing :cpy-file:`Tools/build/regen-configure.sh`:
 ``make regen-configure`` and missing permissions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Since this rule requires `Docker <https://docs.docker.com/desktop>`_ to be
-running, the following can be done on Linux platforms (``systemctl``-based):
-
-.. code-block:: shell
-
-   systemctl status docker          # is the Docker service running?
-   sudo systemctl start docker      # start it if it is not
-   sudo systemctl restart docker    # or restart it if the issue persists
-
 If Docker complains about missing permissions, this Stack Overflow post
 could be useful in solving the issue: `How to fix docker: permission denied
 <https://stackoverflow.com/q/48957195/9579194>`_.
 
-Once the Docker service is running, check that you have an `Ubuntu
-$CONFIGURE_UBUNTU_VERSION$ image <https://hub.docker.com/_/ubuntu>`_,
-or pull it if it is not case:
-
-.. code-block:: shell
-
-   # check for the Docker image presence
-   docker images ubuntu:$CONFIGURE_UBUNTU_VERSION$
-   # pull the Docker image if needed
-   docker image pull ubuntu:$CONFIGURE_UBUNTU_VERSION$
-
-.. tip::
-
-   If the issue persists, you may try `podman <https://podman.io/>`_.
-   The commands for listing or pulling an image are the same as ``docker``.
+We also recommend using `podman <https://podman.io/docs/installation>`_
+instead of ``docker`` since the former does not require a background
+service, or does not create files owned by the ``root`` user in some
+cases.
 
 Missing ``Py_BUILD_CORE`` define when using internal headers
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^