don't use a docker hub image in CI

[TomasTomecek]

...since tests fail on reaching the pull quota:

____________________________ test_build_basic_image ____________________________

target_image = 'registry.example.com/ab-test-qxslfuazgtfv:oldest'
tmpdir = local('/tmp/pytest-of-root/pytest-0/test_build_basic_image0')

    def test_build_basic_image(target_image, tmpdir):
        cmd = ["build", basic_playbook_path, base_image, target_image]
>       ab(cmd, str(tmpdir))

cmd        = ['build', '/root/git-source/tests/data/basic_playbook.yaml', 'docker.io/library/python:3-alpine', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']
target_image = 'registry.example.com/ab-test-qxslfuazgtfv:oldest'
tmpdir     = local('/tmp/pytest-of-root/pytest-0/test_build_basic_image0')

tests/functional/test_buildah.py:34: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
tests/conftest.py:71: in ab
    subprocess.check_call(cmd, cwd=project_dir, env=env)
        args       = ['build', '/root/git-source/tests/data/basic_playbook.yaml', 'docker.io/library/python:3-alpine', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']
        cmd        = ['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', ...]
        env        = None
        ignore_result = False
        return_output = False
        tmpdir_path = '/tmp/pytest-of-root/pytest-0/test_build_basic_image0'
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

popenargs = (['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', ...],)
kwargs = {'cwd': '/root/git-source', 'env': None}, retcode = 2
cmd = ['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', ...]

    def check_call(*popenargs, **kwargs):
        """Run command with arguments.  Wait for command to complete.  If
        the exit code was zero then return, otherwise raise
        CalledProcessError.  The CalledProcessError object will have the
        return code in the returncode attribute.
    
        The arguments are the same as for the call function.  Example:
    
        check_call(["ls", "-l"])
        """
        retcode = call(*popenargs, **kwargs)
        if retcode:
            cmd = kwargs.get("args")
            if cmd is None:
                cmd = popenargs[0]
>           raise CalledProcessError(retcode, cmd)
E           subprocess.CalledProcessError: Command '['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', '/root/git-source/tests/data/basic_playbook.yaml', 'docker.io/library/python:3-alpine', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']' returned non-zero exit status 2.

cmd        = ['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', ...]
kwargs     = {'cwd': '/root/git-source', 'env': None}
popenargs  = (['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', ...],)
retcode    = 2

/usr/lib64/python3.9/subprocess.py:373: CalledProcessError
----------------------------- Captured stderr call -----------------------------
16:34:21.155 conftest.py       DEBUG  cmd = ['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', '/root/git-source/tests/data/basic_playbook.yaml', 'docker.io/library/python:3-alpine', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']
16:36:28.912 utils.py          ERROR  Error initializing source docker://python:3-alpine: Error reading manifest 3-alpine in docker.io/library/python: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
16:36:28.915 buildah_builder.py ERROR  Unable to create or run a container using docker.io/library/python:3-alpine with buildah
Error initializing source docker://python:3-alpine: Error reading manifest 3-alpine in docker.io/library/python: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
There was an error during execution: Command '['buildah', 'from', '--name', 'registry-example-com-ab-test-qxslfuazgtfv-oldest-20210108-163421559000-cont-20210108163421702883', 'docker.io/library/python:3-alpine']' returned non-zero exit status 125.
------------------------------ Captured log call -------------------------------
DEBUG    ansible_bender:conftest.py:63 cmd = ['python3', '-m', 'ansible_bender.cli', '--database-dir', '/tmp/pytest-of-root/pytest-0/test_build_basic_image0', 'build', '/root/git-source/tests/data/basic_playbook.yaml', 'docker.io/library/python:3-alpine', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']
--------------------------- Captured stdout teardown ---------------------------
Command '['buildah', 'rmi', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']' returned non-zero exit status 125.
--------------------------- Captured stderr teardown ---------------------------
16:36:29.026 buildah_builder.py DEBUG  running command: rmi
16:36:29.026 utils.py          INFO   running command: "['buildah', 'rmi', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']"
16:36:29.026 utils.py          DEBUG  buildah rmi registry.example.com/ab-test-qxslfuazgtfv:oldest
16:36:29.083 utils.py          DEBUG  could not get image "registry.example.com/ab-test-qxslfuazgtfv:oldest": identifier is not an image
---------------------------- Captured log teardown -----------------------------
DEBUG    ansible_bender.builders.buildah_builder:buildah_builder.py:185 running command: rmi
INFO     ansible_bender.utils:utils.py:84 running command: "['buildah', 'rmi', 'registry.example.com/ab-test-qxslfuazgtfv:oldest']"
DEBUG    ansible_bender.utils:utils.py:85 buildah rmi registry.example.com/ab-test-qxslfuazgtfv:oldest
DEBUG    ansible_bender.utils:utils.py:57 could not get image "registry.example.com/ab-test-qxslfuazgtfv:oldest": identifier is not an image

[TomasTomecek]

Fixed by #270