The **attrs** and **cattrs** packages version is incompatible.
Check command:
`pip check --use-feature=2020-resolver`

Code file: https://github.com/apache/airflow/blob/master/setup.py
Commit hash: 9150330
Line number:
694: 'attrs~=19.3'
696: 'cattrs~=1.0'

It will caused the final installed **attrs** version is higher than 20.1.0.

Why this happen?
From the dependency setting of **cattrs**:
https://github.com/Tinche/cattrs/blob/master/setup.py
Commit hash: 2f401b9
Line number:
12: "attrs >= 20.1.0"

setup.py
'mysqlclient>=1.3.6,<1.4',
]
odbc = [
    'pyodbc',
]
oracle = [
    'cx_Oracle>=5.1.2',
]
pagerduty = [
    'pdpyras>=4.1.2,<5',
]
papermill = [
    'papermill[all]>=1.2.1',
    'nteract-scrapbook[all]>=0.3.1',
]
password = [
    'bcrypt>=2.0.0',
    'flask-bcrypt>=0.7.1',
]
pinot = [
    'pinotdb==0.1.1',
]
plexus = [
    'arrow>=0.16.0',
]
postgres = [
    'psycopg2-binary>=2.7.4',
]
presto = [
    'presto-python-client>=0.7.0,<0.8'