The dependencies in Alphas are currently >= 2.0.0 and should be >=2.0.0a0 in order to work with Alphas in cases which are not PEP 440-compliant.

According to https://www.python.org/dev/peps/pep-0440/, >= 2.0.0 should also work with alpha/beta releases (a1/a2) but in some cases it does not (https://apache-airflow.slack.com/archives/C0146STM600/p1602774750041800) 

Changing to ">=2.0.0a0" should help.
provider_packages/setup_provider_packages.py
"""
    Get git command to run for the current repo from the current folder (which is the package folder).
    :param base_commit: if present - base commit from which to start the log from
    :return: git command to run
    """
    git_cmd = ["git", "log", "apache-https-for-providers/master",
               "--pretty=format:%H %h %cd %s", "--date=short"]
    if base_commit:
        git_cmd.append(f"{base_commit}...HEAD")
    git_cmd.extend(['--', '.'])
    return git_cmd
def store_current_changes(provider_package_path: str,