Run pyupgrade for 3.8

[daveisfera]

Pull Request check-list

• Do tests and lints pass with this change? No new failures on my local
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)? I don't know how to do this
• Is the new or changed code fully tested? No new code and changes should be safe/not change functionality
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)? N/A
• Is there an example added to the examples folder (if applicable)? N/A
• Was the change added to CHANGES file? Not needed since 3.8 is currently the minimum version

Description of change

Run pyupgrade with -py38-plus to remove anything from old versions

[gerzse]

@daveisfera Thanks for this contribution!

The linters in the CI compain now:

redis/__init__.py:1:1: F401 'sys' imported but unused
redis/__init__.py:38:1: I004 isort found an unexpected blank line in imports
redis/__init__.py:39:1: I001 isort found an import in the wrong position
redis/utils.py:2:1: F401 'sys' imported but unused

It seems that pyupgrade does not remove unused imports. Could you, please take care of this, so we can merge the PR? Thanks!

[daveisfera]

It seems that pyupgrade does not remove unused imports. Could you, please take care of this, so we can merge the PR? Thanks!

Done

[gerzse]

@daveisfera Sorry, one more linter error showed up, in one of the test files. Some indentation in the set literals, it seems. You can try invoke linters locally, to make sure everything passes.

[daveisfera]

I don't think my PR was the cause of that and it was a version change or something else or something, but I fixed it anyways

[gerzse]

Thanks @daveisfera !