Add setup.cfg for apache-airflow-upgrade-check (#12517)

Nothing currently uses this setup.cfg from this folder -- automation for
that will follow shortly.

Now that there is a place list deps for upgrade-check I have moved
`packaging` and `importlib_meta` to test_requires of the main dist.

Build a py2+py3 wheel.

(cherry picked from commit deb7fc0)

airflow/upgrade/setup.cfg

@@ -0,0 +1,64 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+[metadata]
+version=1.0.0
+name = apache-airflow-upgrade-check
+description = Check for compatibility between Airflow versions
+long_description = file: airflow/upgrade/README.md
+long_description_content_type = text/markdown
+url = https://airflow.apache.org
+author = Apache Airflow PMC
+author-email = dev@airflow.apache.org
+license = Apache License 2.0
+license_files =
+   LICENSE
+   NOTICE
+classifiers =
+    Development Status :: 5 - Production/Stable
+    Intended Audience :: Developers
+    License :: OSI Approved :: Apache Software License
+    Programming Language :: Python :: 2.7
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+keywords = airflow, upgrade
+project_urls =
+    Source Code=https://github.com/apache/airflow
+    Bug Tracker=https://github.com/apache/airflow/issues
+    Documentation=https://airflow.apache.org/docs/
+
+[options]
+packages = find:
+install_requires =
+    apache-airflow>=1.10.13,<3
+    importlib-metadata~=2.0; python_version<"3.8"
+    packaging
+python_requires = >=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*
+setup_requires =
+    setuptools>=40.0
+    wheel
+zip_safe = no
+
+[options.packages.find]
+include =
+  airflow.upgrade
+  airflow.upgrade.*
+
+[bdist_wheel]
+universal=1

setup.py

@@ -426,12 +426,14 @@ def write_version(filename=os.path.join(*[my_dir, "airflow", "git_version"])):
     'flaky',
     'freezegun',
     'gitpython',
+    'importlib-metadata~=2.0; python_version<"3.8"',
     'ipdb',
     'jira',
     'mock;python_version<"3.3"',
     'mongomock',
     'moto==1.3.14',  # TODO - fix Datasync issues to get higher version of moto:
                      #        See: https://github.com/apache/airflow/issues/10985
+    'packaging',
     'parameterized',
     'paramiko',
     'pre-commit',
@@ -445,7 +447,7 @@ def write_version(filename=os.path.join(*[my_dir, "airflow", "git_version"])):
     'pywinrm',
     'qds-sdk>=1.9.6',
     'requests_mock',
-    'yamllint'
+    'yamllint',
 ]
 ############################################################################################################
 # IMPORTANT NOTE!!!!!!!!!!!!!!!