fix: upper limits are incorrect in requires-python

[waketzheng]

Topic

Fixes #449

Checklist

• pre-commit run --all-files
• tox

[waketzheng]

@TheKevJames How to resolve the ci failure? Error detail:

upload: commands[0]> coveralls --verbose
Missing .coveralls.yml file. Using only env variables.
Error running coveralls: Not on TravisCI. You have to provide either repo_token in .coveralls.yml or set the COVERALLS_REPO_TOKEN env var.
Traceback (most recent call last):
  File "/root/project/coveralls/cli.py", line 65, in main
    coverallz = Coveralls(
  File "/root/project/coveralls/api.py", line 47, in __init__
    self.ensure_token()
  File "/root/project/coveralls/api.py", line 60, in ensure_token
    raise CoverallsException(
coveralls.exception.CoverallsException: Not on TravisCI. You have to provide either repo_token in .coveralls.yml or set the COVERALLS_REPO_TOKEN env var.
upload: exit 1 (0.23 seconds) /root/project> coveralls --verbose pid=2148