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
"""
    Gets long description of the package.
    :param provider_package_id: package id
    :param backport_packages: whether to prepare regular (False) or backport (True) packages
    :return: content of the description (BACKPORT_README/README file)
    """
    package_folder = get_target_providers_package_folder(provider_package_id)
    readme_file = os.path.join(package_folder, "BACKPORT_README.md" if backport_packages else "README.md")
    if not os.path.exists(readme_file):
        return ""
    with open(os.path.join(package_folder, "BACKPORT_README.md" if backport_packages else "README.md"),
              encoding='utf-8', mode="r") as file:
        readme_contents = file.read()
    copying = True
    long_description = ""
    for line in readme_contents.splitlines(keepends=True):
        if line.startswith("**Table of contents**"):
            copying = False
            continue
        header_line = "## Backport package" if backport_packages else "## Provider package"
        if line.startswith(header_line):
            copying = True
        if copying:
            long_description += line
    return long_description
def get_package_release_version(provider_package_id: str,