openstack-tox-py39 failing attempt install dataclasses from test-requirements.txt

[Arx Cruz]

The package dataclasses is no longer required for python version > 3.7, attempt to install it, fails because this package doesn't exist once it's included directly in python.

from https://github.com/ericvsmith/dataclasses:

Because dataclasses will be included in Python 3.7, any discussion of dataclass features should occur on the python-dev mailing list at https://mail.python.org/mailman/listinfo/python-dev. At this point this repo should only be used for historical purposes (it's where the original dataclasses discussions took place) and for discussion of the actual backport to Python 3.6.

[Ronelle Landy (rlandy)]

https://review.opendev.org/c/openstack/tripleo-ci/+/828826

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/tripleo-ci/+/828826
Committed: https://opendev.org/openstack/tripleo-ci/commit/0c2cf3e63ca423977e8eb4d73de738b3c0cb6eed
Submitter: "Zuul (22348)"
Branch: master

commit 0c2cf3e63ca423977e8eb4d73de738b3c0cb6eed
Author: Arx Cruz <email address hidden>
Date: Fri Feb 11 10:22:54 2022 +0100

    Install dataclasses only for python version < 3.7

    According [1] the dataclasses is already included in python 3.7 and
    foward versions. Attempt to install it fails because the package
    doesn't exist. This patch fix the test-requirements.txt to only
    install it when python version is lower than 3.7.

    1 - https://github.com/ericvsmith/dataclasses

    Closes-Bug: #1960603
    Change-Id: Iab540e69b698205cbb9c75061313aad9d9c2d3c4