Create antsibull-stub package config for backwards compatibility

This project can be published to PyPI to maintain backwards
compatibility.

antsibull-stub/LICENSE

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+../LICENSE

antsibull-stub/LICENSES

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+../LICENSES

antsibull-stub/README.md

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+<!--
+Copyright (c) Ansible Project
+GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+SPDX-License-Identifier: GPL-3.0-or-later
+-->
+
+# antsibull PyPI stub package
+
+The `antsibull` project has been renamed to `antsibull-build`.
+This is an empty stub package for backwards compatibility.

antsibull-stub/pyproject.toml

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+# Copyright (c) Ansible Project
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "antsibull"
+version = "0.66.0"
+description = "The antsibull project has been renamed to antsibull-build"
+license = "GPL-3.0-or-later AND Python-2.0.1"
+license-files = {globs=["LICENSES/*.txt"]}
+readme = "README.md"
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Framework :: Ansible",
+    "Intended Audience :: Developers",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Typing :: Typed",
+]
+requires-python = ">=3.9"
+dependencies = [
+    "antsibull-build>=0.66.0"
+]
+
+[[project.authors]]
+name = "Toshio Kuratomi"
+email = "[email protected]"
+
+[[project.authors]]
+name = "Felix Fontein"
+email = "[email protected]"
+
+[[project.maintainers]]
+name = "Felix Fontein"
+email = "[email protected]"
+
+[[project.maintainers]]
+name = "Maxwell G"
+email = "[email protected]"
+
+[project.urls]
+"New package" = "https://pypi.org/project/antsibull-build"
+
+[project.optional-dependencies]
+# User-facing extras
+clipboard = [
+    "antsibull-build[clipboard]"
+]
+all = [
+    "antsibull-build[all]",
+]
+
+[tool.hatch.build.targets.wheel]
+# This is an empty package
+bypass-selection = true

changelogs/fragments/629-antsibull-stub.yaml

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+---
+breaking_changes:
+  - "The name of this project has been changed from ``antsibull`` to
+    ``antsibull-build`` to reflect that it provides the ``antsibull-build``
+    command and disambiguate this project from the other antsibull projects.
+    For backwards compatibility purposes, the ``antsibull`` project on PyPI
+    has been converted to an empty stub package that requires
+    ``antsibull-build``, but users should immediately switch to the new name.
+    The Git repository has also been moved to
+    https://github.com/ansible-community/antsibull-build
+    (https://github.com/ansible-community/antsibull/issues/627,
+    https://github.com/ansible-community/antsibull/pull/629)."